Comparison of programming languages (string functions) explained

String functions are used in computer programming languages to manipulate a string or query information about a string (some do both).

Most programming languages that have a string datatype will have some string functions although there may be other low-level ways within each language to handle strings directly. In object-oriented languages, string functions are often implemented as properties and methods of string objects. In functional and list-based languages a string is represented as a list (of character codes), therefore all list-manipulation procedures could be considered string functions. However such languages may implement a subset of explicit string-specific functions as well.

For function that manipulate strings, modern object-oriented languages, like C# and Java have immutable strings and return a copy (in newly allocated dynamic memory), while others, like C manipulate the original string unless the programmer copies data to a new string. See for example Concatenation below.

The most basic example of a string function is the length(string) function. This function returns the length of a string literal.

e.g. length("hello world") would return 11.

Other languages may have string functions with similar or exactly the same syntax or parameters or outcomes. For example, in many languages the length function is usually represented as len(string). The below list of common functions aims to help limit this confusion.

Common string functions (multi language reference)

String functions common to many languages are listed below, including the different names used. The below list of common functions aims to help programmers find the equivalent function in a language. Note, string concatenation and regular expressions are handled in separate pages. Statements in guillemets (« … ») are optional.

CharAt

Definition	charAt(string,integer) returns character.
Description	Returns character at index in the string.
Equivalent	See substring of length 1 character.

Format	Languages	Base index
''string''[''i'']	ALGOL 68, APL, Julia, Pascal, Object Pascal (Delphi), Seed7	1
''string''[''i'']	C, C++, C#, Cobra, D, FreeBASIC, Go, Python, PHP, Ruby, Windows PowerShell, JavaScript, APL	0
''string''{''i''}	PHP (deprecated in 5.3)	0
''string''(''i'')	Ada	≥1
Mid(''string'',i,1)	VB	1
MID$(''string'',i,1)	BASIC	1
''string''.Chars(''i'')	VB.NET	0
''string''(''i'':''i'')	Fortran	1
''string''.charAt(''i'')	Java, JavaScript	0
''string''.[''i'']	OCaml, F#	0
''string''.chars.nth(''i'')	Rust^[1]	0
''string''[''i'',''1'']	Pick Basic	1
String.sub (''string'', ''i'')	Standard ML	0
''string'' !	i	Haskell	0
(string-ref ''string'' ''i'')	Scheme	0
(char ''string'' ''i'')	Common Lisp	0
(elt ''string'' ''i'')	ISLISP	0
(get ''string'' ''i'')	Clojure	0
substr(''string'', ''i'', 1)	Perl 5	0
substr(''string'', ''i'', 1) string.substr(''i'', 1)	Raku	0
substr(''string'', ''i'', 1)	PL/I	1
''string''.at(''i'')	C++ (STL) (w/ bounds checking)	0
lists:nth(''i'', ''string'')	Erlang	1
[''string'' characterAtIndex:''i'']	Objective-C (NSString * only)	0
string.sub(''string'', ''i'', ''i'') (''string''):sub(''i'', ''i'')	Lua	1
''string'' at: ''i''	Smalltalk (w/ bounds checking)	1
string index ''string i''	Tcl	0
StringTake[''string'', {''i''}]	Mathematica, Wolfram Language	1
''string''@''i''	Eiffel	1
''string'' (''i'':1)	COBOL	1
${''string_param'':''i'':1}	Bash	0
''i''⌷''string''	APL	0 or 1

var MyStr: string = 'Hello, World'; MyChar: Char;begin MyChar := MyStr[2]; // 'e'

# Example in ALGOL 68 #
"Hello, World"[2];             // 'e'

// Example in C

1. include // for printf

char MyStr[] = "Hello, World";printf("%c", *(MyStr+1)); // 'e'printf("%c", *(MyStr+7)); // 'W'printf("%c", MyStr[11]); // 'd'printf("%s", MyStr); // 'Hello, World'printf("%s", "Hello(2), World(2)"); // 'Hello(2), World(2)'

// Example in C++

1. include // for "cout"
2. include // for "string" data type

using namespace std;char MyStr1[] = "Hello(1), World(1)";string MyStr2 = "Hello(2), World(2)";cout << "Hello(3), World(3)"; // 'Hello(3), World(3)'cout << MyStr2[6]; // '2'cout << MyStr1.substr (5, 3); // '(1)'

// Example in C#"Hello, World"[2]; // 'l'

1. Example in Perl 5

substr("Hello, World", 1, 1); # 'e'

1. Examples in Python

"Hello, World"[2] # 'l'"Hello, World"[-3] # 'r'

1. Example in Raku

"Hello, World".substr(1, 1); # 'e'

' Example in Visual BasicMid("Hello, World",2,1)

' Example in Visual Basic .NET"Hello, World".Chars(2) ' "l"c

" Example in Smalltalk "'Hello, World' at: 2. "$e"

//Example in Rust"Hello, World".chars.nth(2); // Some('l')

Compare (integer result)

Definition	compare(string<sub>1</sub>,string<sub>2</sub>) returns integer.
Description	Compares two strings to each other. If they are equivalent, a zero is returned. Otherwise, most of these routines will return a positive or negative result corresponding to whether string1 is lexicographically greater than, or less than, respectively, than string2. The exceptions are the Scheme and Rexx routines which return the index of the first mismatch, and Smalltalk which answer a comparison code telling how the receiver sorts relative to string parameter.

Format	Languages
IF ''string<sub>1</sub>''<''string<sub>2</sub>'' THEN -1 ELSE ABS (''string<sub>1</sub>''>''string<sub>2</sub>'') FI	ALGOL 68
cmp(''string<sub>1</sub>'', ''string<sub>2</sub>'')	Python 2
(''string<sub>1</sub>'' > ''string<sub>2</sub>'') - (''string<sub>1</sub>'' < ''string<sub>2</sub>'')	Python
[[strcmp]](''string<sub>1</sub>'', ''string<sub>2</sub>'')	C, PHP
std.string.cmp(''string<sub>1</sub>'', ''string<sub>2</sub>'')	D
StrComp(''string<sub>1</sub>'', ''string<sub>2</sub>'')	VB, Object Pascal (Delphi)
''string<sub>1</sub>'' cmp ''string<sub>2</sub>''	Perl, Raku
''string<sub>1</sub>'' compare: ''string<sub>2</sub>''	Smalltalk (Squeak, Pharo)
''string<sub>1</sub>'' <=> ''string<sub>2</sub>''	Ruby, C++ (STL, C++20)^[2]
''string<sub>1</sub>''.compare(''string<sub>2</sub>'')	C++ (STL), Swift (Foundation)
compare(''string<sub>1</sub>'', ''string<sub>2</sub>'')	Rexx, Seed7
CompareStr(''string<sub>1</sub>'', ''string<sub>2</sub>'')	Pascal, Object Pascal (Delphi)
''string<sub>1</sub>''.compareTo(''string<sub>2</sub>'')	Cobra, Java
''string<sub>1</sub>''.CompareTo(''string<sub>2</sub>'')	VB .NET, C#, F#
(compare ''string<sub>1</sub>'' ''string<sub>2</sub>'')	Clojure
(string= ''string<sub>1</sub>'' ''string<sub>2</sub>'')	Common Lisp
(string-compare ''string<sub>1</sub>'' ''string<sub>2</sub>'' ''p<'' ''p='' ''p>'')	Scheme (SRFI 13)
(string= ''string<sub>1</sub>'' ''string<sub>2</sub>'')	ISLISP
compare ''string<sub>1</sub>'' ''string<sub>2</sub>''	OCaml
String.compare (''string<sub>1</sub>'', ''string<sub>2</sub>'')	Standard ML^[3]
compare ''string<sub>1</sub>'' ''string<sub>2</sub>''	Haskell^[4]
[string]::Compare(''string<sub>1</sub>'', ''string<sub>2</sub>'')	Windows PowerShell
[''string<sub>1</sub>'' compare:''string<sub>2</sub>'']	Objective-C (NSString * only)
LLT(''string<sub>1</sub>'',''string<sub>2</sub>'') LLE(''string<sub>1</sub>'',''string<sub>2</sub>'') LGT(''string<sub>1</sub>'',''string<sub>2</sub>'') LGE(''string<sub>1</sub>'',''string<sub>2</sub>'')	Fortran^[5]
''string<sub>1</sub>''.localeCompare(''string<sub>2</sub>'')	JavaScript
bytes.Compare([]byte(''string<sub>1</sub>''), []byte(''string<sub>2</sub>''))	Go
string compare ''string<sub>1</sub>'' ''string<sub>2</sub>''	Tcl
compare(''string<sub>1</sub>'',''string<sub>2</sub>'',''count'')	PL/I^[6]
''string<sub>1</sub>''.cmp(''string<sub>2</sub>'')	Rust^[7]

1. Example in Perl 5

"hello" cmp "world"; # returns -1

1. Example in Python

cmp("hello", "world") # returns -1

1. Examples in Raku

"hello" cmp "world"; # returns Less"world" cmp "hello"; # returns More"hello" cmp "hello"; # returns Same

/** Example in Rexx */compare("hello", "world") /* returns index of mismatch: 1 */

Example in Scheme(use-modules (srfi srfi-13))

returns index of mismatch: 0(string-compare "hello" "world" values values values)

Compare (relational operator-based, Boolean result)

Definition	string<sub>1</sub> OP string<sub>2</sub> OR (compare string<sub>1</sub> string<sub>2</sub>) returns Boolean.
Description	Lexicographically compares two strings using a relational operator or function. Boolean result returned.

Format	Languages
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of =, <>, <, >, <= and >=	Pascal, Object Pascal (Delphi), OCaml, Seed7, Standard ML, BASIC, VB, VB .NET, F#
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of =, /=, ≠, <, >, <=, ≤ and ≥; Also: EQ, NE, LT, LE, GE and GT	ALGOL 68
(stringOP? ''string<sub>1</sub>'' ''string<sub>2</sub>''), where OP can be any of =, -ci=, <, -ci<, >, -ci>, <=, -ci<=, >= and -ci>= (operators starting with '-ci' are case-insensitive)	Scheme
(stringOP ''string<sub>1</sub>'' ''string<sub>2</sub>''), where OP can be any of =, -ci=, <>, -ci<>, <, -ci<, >, -ci>, <=, -ci<=, >= and -ci>= (operators starting with '-ci' are case-insensitive)	Scheme (SRFI 13)
(stringOP ''string<sub>1</sub>'' ''string<sub>2</sub>''), where OP can be any of =, -equal, /=, -not-equal, <, -lessp, >, -greaterp, <=, -not-greaterp, >= and -not-lessp (the verbal operators are case-insensitive)	Common Lisp
(stringOP ''string<sub>1</sub>'' ''string<sub>2</sub>''), where OP can be any of =, /=, <, >, <=, and >=	ISLISP
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of =, \=, <, >, <= and >=	Rexx
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of =, ¬=, <, >, <=, >=, ¬< and ¬>	PL/I
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of =, /=, <, >, <= and >=	Ada
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of ==, /=, <, >, =< and >=	Erlang
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of ==, /=, <, >, <= and >=	Haskell
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of ''eq'', ''ne'', ''lt'', ''gt'', ''le'' and ''ge''	Perl, Raku
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of ==, !=, <, >, <= and >=	C++ (STL), C#, D, Go, JavaScript, Python, PHP, Ruby, Rust,^[8] Swift
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of -eq, -ceq, -ne, -cne, -lt, -clt, -gt, -cgt, -le, -cle, -ge, and -cge (operators starting with 'c' are case-sensitive)	Windows PowerShell
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of ==, ~=, <, >, <= and >=	Lua
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of =, ~=, <, >, <= and >=	Smalltalk
''string<sub>1</sub>'' OP ''string<sub>2</sub>'', where OP can be any of ==, /=, <, >, <= and >=; Also: .EQ., .NE., .LT., .LE., .GT. and .GE.	Fortran.^[9]
''string<sub>1</sub>'' OP ''string<sub>2</sub>'' where OP can be any of =, <>, <, >, <=, >= as well as worded equivalents	COBOL
''string<sub>1</sub>'' OP ''string<sub>2</sub>'' where OP can be any of ==, <>, <, >, <= and >=	Cobra
''string<sub>1</sub>'' OP ''string<sub>2</sub>'' is available in the syntax, but means comparison of the pointers pointing to the strings, not of the string contents. Use the Compare (integer result) function.	C, Java
''string<sub>1</sub>''.METHOD(''string<sub>2</sub>'') where METHOD is any of eq, ne, gt, lt, ge, le	Rust

% Example in Erlang"hello" > "world". % returns false

1. Example in Raku

"art" gt "painting"; # returns False"art" lt "painting"; # returns True

1. Example in Windows PowerShell

"hello" -gt "world" # returns false

Example in Common Lisp(string> "art" "painting") ; returns nil(string< "art" "painting") ; returns non nil

Concatenation

See also: Concatenation.

Definition	concatenate(string<sub>1</sub>,string<sub>2</sub>) returns string.
Description	Concatenates (joins) two strings to each other, returning the combined string. Note that some languages like C have mutable strings, so really the second string is being appended to the first string and the mutated string is returned.

Format	Languages
''string<sub>1</sub>'' & ''string<sub>2</sub>''	Ada, FreeBASIC, Seed7, BASIC, VB, VB .NET, COBOL (between literals only)
[[strcat]](''string<sub>1</sub>'', ''string<sub>2</sub>'')	C, C++ ([[character (computing)|char]] [[Pointer (computer programming)|*]] only)^[10]
''string<sub>1</sub>'' . ''string<sub>2</sub>''	Perl, PHP
''string<sub>1</sub>'' + ''string<sub>2</sub>''	ALGOL 68, C++ (STL), C#, Cobra, FreeBASIC, Go, Pascal, Object Pascal (Delphi), Java, JavaScript, Windows PowerShell, Python, Ruby, Rust,^[11] F#, Swift, Turing, VB
''string<sub>1</sub>'' ~ ''string<sub>2</sub>''	D, Raku
(string-append ''string<sub>1</sub>'' ''string<sub>2</sub>'')	Scheme, ISLISP
(concatenate 'string ''string<sub>1</sub>'' ''string<sub>2</sub>'')	Common Lisp
(str ''string<sub>1</sub>'' ''string<sub>2</sub>'')	Clojure
''string<sub>1</sub>'' <nowiki>||</nowiki> ''string<sub>2</sub>''	Rexx, SQL, PL/I
''string<sub>1</sub>'' // ''string<sub>2</sub>''	Fortran
''string<sub>1</sub>'' ++ ''string<sub>2</sub>''	Erlang, Haskell
''string<sub>1</sub>'' ^ ''string<sub>2</sub>''	OCaml, Standard ML, F#
[''string<sub>1</sub>'' stringByAppendingString:''string<sub>2</sub>'']	Objective-C (NSString * only)
''string<sub>1</sub>'' .. ''string<sub>2</sub>''	Lua
''string<sub>1</sub>'', ''string<sub>2</sub>''	Smalltalk, APL
''string<sub>1</sub>'' ''string<sub>2</sub>''	SNOBOL
''string<sub>1</sub>string<sub>2</sub>''	Bash
''string<sub>1</sub>'' <> ''string<sub>2</sub>''	Mathematica
concat string1 string2	Tcl

'abc' + 'def'; // returns "abcdef"

// Example in C#"abc" + "def"; // returns "abcdef"

' Example in Visual Basic"abc" & "def" ' returns "abcdef""abc" + "def" ' returns "abcdef""abc" & Null ' returns "abc""abc" + Null ' returns Null

// Example in D"abc" ~ "def"; // returns "abcdef"

Example in common lisp(concatenate 'string "abc " "def " "ghi") ; returns "abc def ghi"

1. Example in Perl 5

"abc" . "def"; # returns "abcdef""Perl " . 5; # returns "Perl 5"

1. Example in Raku

"abc" ~ "def"; # returns "abcdef""Perl " ~ 6; # returns "Perl 6"

Contains

Definition	contains(''string'',''substring'') returns boolean
Description	Returns whether string contains substring as a substring. This is equivalent to using Find and then detecting that it does not result in the failure condition listed in the third column of the Find section. However, some languages have a simpler way of expressing this test.
Related	Find

Format	Languages
''string_in_string''(''string'', '''loc int''', ''substring'')	ALGOL 68
''ContainsStr''(''string'', ''substring'')	Object Pascal (Delphi)
strstr(''string'', ''substring'') != NULL	C, C++ (char * only)
''string''.Contains(''substring'')	C#, VB .NET, Windows PowerShell, F#
''string''.contains(''substring'')	Cobra, Java (1.5+), Raku, Rust,^[12] C++ (C++23)^[13]
''string''.indexOf(''substring'') >= 0	JavaScript
strpos(''string'', ''substring'') !== false	PHP
str_contains(''string'', ''substring'')	PHP (8+)
pos(''string'', ''substring'') <> 0	Seed7
''substring'' in ''string''	Cobra, Python (2.3+)
string.find(''string'', ''substring'') ~= nil	Lua
''string''.include?(''substring'')	Ruby
Data.List.isInfixOf ''substring'' ''string''	Haskell (GHC 6.6+)
''string'' includesSubstring: ''substring''	Smalltalk (Squeak, Pharo, Smalltalk/X)
String.isSubstring ''substring'' ''string''	Standard ML
(search ''substring'' ''string'')	Common Lisp
(not (null (string-index ''substring'' ''string'')))	ISLISP
(substring? ''substring'' ''string'')	Clojure
! StringFreeQ[''string'', ''substring'']	Mathematica
index(''string'', ''substring'', ''startpos'')>0	Fortran, PL/I^[14]
index(''string'', ''substring'', ''occurrence'')>0	Pick Basic
strings.Contains(''string'', ''substring'')	Go
''string''.find(''substring'') != string::npos	C++
[''string'' containsString:''substring'']	Objective-C (NSString * only, iOS 8+/OS X 10.10+)
''string''.rangeOfString(''substring'') != nil	Swift (Foundation)
∨/''substring''⍷''string''	APL

¢ Example in ALGOL 68 ¢ string in string("e", loc int, "Hello mate"); ¢ returns true ¢ string in string("z", loc int, "word"); ¢ returns false ¢

// Example In C#"Hello mate".Contains("e"); // returns true"word".Contains("z"); // returns false

1. Example in Python

"e" in "Hello mate" # returns true"z" in "word" # returns false

1. Example in Raku

"Good morning!".contains('z') # returns False"¡Buenos días!".contains('í'); # returns True

" Example in Smalltalk "'Hello mate' includesSubstring: 'e' " returns true "'word' includesSubstring: 'z' " returns false "

Equality

Tests if two strings are equal. See also

1. Compare

and

1. Compare

. Note that doing equality checks via a generic Compare with integer result is not only confusing for the programmer but is often a significantly more expensive operation; this is especially true when using "C-strings".

Format	Languages
''string<sub>1</sub>'' == ''string<sub>2</sub>''	Python, C++ (STL), C#, Cobra, Go, JavaScript (similarity), PHP (similarity), Ruby, Rust, Erlang, Haskell, Lua, D, Mathematica, Swift
''string<sub>1</sub>'' === ''string<sub>2</sub>''	JavaScript, PHP
''string<sub>1</sub>'' == ''string<sub>2</sub>'' ''string<sub>1</sub>'' .EQ. ''string<sub>2</sub>''	Fortran
strcmp(''string<sub>1</sub>'', ''string<sub>2</sub>'') == 0	C
(string=? ''string<sub>1</sub>'' ''string<sub>2</sub>'')	Scheme
(string= ''string<sub>1</sub>'' ''string<sub>2</sub>'')	Common Lisp, ISLISP
''string<sub>1</sub>'' = ''string<sub>2</sub>''	ALGOL 68, Ada, Object Pascal (Delphi), OCaml, Pascal, Rexx, Seed7, Standard ML, BASIC, VB, VB .NET, F#, Smalltalk, PL/I, COBOL
test ''string<sub>1</sub>'' = ''string<sub>2</sub>'' [ ''string<sub>1</sub>'' = ''string<sub>2</sub>'' ]	Bourne Shell
''string<sub>1</sub>'' eq ''string<sub>2</sub>''	Perl, Raku
''string<sub>1</sub>''.equals(''string<sub>2</sub>'')	Cobra, Java
''string<sub>1</sub>''.Equals(''string<sub>2</sub>'')	C#
''string<sub>1</sub>'' -eq ''string<sub>2</sub>'' [string]::Equals(''string<sub>1</sub>'', ''string<sub>2</sub>'')	Windows PowerShell
[''string<sub>1</sub>'' isEqualToString:''string<sub>2</sub>''] [''string<sub>1</sub>'' isEqual:''string<sub>2</sub>'']	Objective-C (NSString * only)
''string<sub>1</sub>'' ≡ ''string<sub>2</sub>''	APL
''string<sub>1</sub>''.eq(''string<sub>2</sub>'')	Rust

// Example in C#"hello"

"world" // returns false

' Example in Visual Basic"hello" = "world" ' returns false

1. Examples in Perl 5

'hello' eq 'world' # returns 0'hello' eq 'hello' # returns 1

1. Examples in Raku

'hello' eq 'world' # returns False'hello' eq 'hello' # returns True

1. Example in Windows PowerShell

"hello" -eq "world" # returns false

⍝ Example in APL'hello' ≡ 'world' ⍝ returns 0

Find

Definition	find(''string'',''substring'') returns integer
Description	Returns the position of the start of the first occurrence of substring in string. If the substring is not found most of these routines return an invalid index value – -1 where indexes are 0-based, 0 where they are 1-based – or some value to be interpreted as Boolean FALSE.
Related	instrrev

Format	Languages	If not found
string in string(substring, pos, ''string[startpos:]'')	ALGOL 68	returns BOOL: TRUE or FALSE, and position in REF INT pos.
InStr(«''startpos'',»''string'',''substring'')	VB (positions start at 1)	returns 0
INSTR$(''string'',''substring'')	BASIC (positions start at 1)	returns 0
index(''string'',''substring'')	AWK	returns 0
index(''string'',''substring''«,''startpos''»)	Perl 5	returns −1
index(''string'',''substring''«,''startpos''») ''string''.index(''substring'',«,''startpos''»)	Raku	returns Nil
instr(«''startpos'',»''string'',''substring'')	FreeBASIC	returns 0
strpos(''string'',''substring''«,''startpos''»)	PHP	returns FALSE
locate(''string'', ''substring'')	Ingres	returns string length + 1
strstr(''string'', ''substring'')	C, C++ ([[character (computing)|char]] [[Pointer (computer programming)|*]] only, returns pointer to first character)	returns NULL
std.string.indexOf(''string'', ''substring'')	D	returns −1
pos(''string'', ''substring''«, ''startpos''»)	Seed7	returns 0
strings.Index(''string'', ''substring'')	Go	returns −1
pos(''substring'', ''string'')	Pascal, Object Pascal (Delphi)	returns 0
pos(''substring'', ''string''«,''startpos''»)	Rexx	returns 0
''string''.find(''substring''«,''startpos''»)	C++ (STL)	returns std::string::npos
''string''.find(''substring''«,''startpos''«,''endpos''»»)	Python	returns −1
''string''.index(''substring''«,''startpos''«,''endpos''»»)		raises ValueError
''string''.index(''substring''«,''startpos''»)	Ruby	returns nil
''string''.indexOf(''substring''«,''startpos''»)	Java, JavaScript	returns −1
''string''.IndexOf(''substring''«,''startpos''«, ''charcount''»»)	VB .NET, C#, Windows PowerShell, F#	returns −1
string:str(''string'', ''substring'')	Erlang	returns 0
(string-contains ''string'' ''substring'')	Scheme (SRFI 13)	returns #f
(search ''substring'' ''string'')	Common Lisp	returns NIL
(string-index ''substring'' ''string'')	ISLISP	returns nil
List.findIndex (List.isPrefixOf ''substring'') (List.tails ''string'')	Haskell (returns only index)	returns Nothing
Str.search_forward (Str.regexp_string ''substring'') ''string'' 0	OCaml	raises Not_found
Substring.size (#1 (Substring.position ''substring'' (Substring.full ''string'')))	Standard ML	returns string length
[''string'' rangeOfString:''substring''].location	Objective-C (NSString * only)	returns NSNotFound
string.find(''string'', ''substring'') (''string''):find(''substring'')	Lua	returns nil
''string'' indexOfSubCollection: ''substring'' startingAt: ''startpos'' ifAbsent: ''aBlock'' ''string'' findString: ''substring'' startingAt: ''startpos''	Smalltalk (Squeak, Pharo)	evaluate aBlock which is a block closure (or any object understanding value) returns 0
startpos = INDEX(''string'', ''substring'' «,''back''» «, ''kind''»)	Fortran	returns 0 if substring is not in string; returns LEN(string)+1 if substring is empty
POSITION(''substring'' IN ''string'')	SQL	returns 0 (positions start at 1)
index(''string'', ''substring'', ''startpos'')	PL/I	returns 0 (positions start at 1)
index(''string'', ''substring'', ''occurrence'')	Pick Basic	returns 0 if occurrence of substring is not in string; (positions start at 1)
''string''.indexOf(''substring''«,''startpos''«, ''charcount''»»)	Cobra	returns −1
string first ''substring string startpos''	Tcl	returns −1
(''substring''⍷''string'')⍳1	APL	returns 1 + the last position in string
''string''.find(''substring'')	Rust^[15]	returns None

Examples

• Common Lisp

(search "e" "Hello mate") ; returns 1(search "z" "word") ; returns NIL

• C#

"Hello mate".IndexOf("e"); // returns 1"Hello mate".IndexOf("e", 4); // returns 9"word".IndexOf("z"); // returns -1

• Raku

"Hello, there!".index('e') # returns 1"Hello, there!".index('z') # returns Nil

• Scheme

(use-modules (srfi srfi-13))(string-contains "Hello mate" "e") ; returns 1(string-contains "word" "z") ; returns #f

• Visual Basic

' Examples inInStr("Hello mate", "e") ' returns 2InStr(5, "Hello mate", "e") ' returns 10InStr("word", "z") ' returns 0

• Smalltalk

'Hello mate' indexOfSubCollection:'ate' "returns 8"

'Hello mate' indexOfSubCollection:'late' "returns 0"

I'Hello mate' indexOfSubCollection:'late' ifAbsent:[99 ] "returns 99"

'Hello mate' indexOfSubCollection:'late' ifAbsent:[self error ] "raises an exception"

Find character

Definition	find_character(''string'',''char'') returns integer
Description	Returns the position of the start of the first occurrence of the character char in string. If the character is not found most of these routines return an invalid index value – -1 where indexes are 0-based, 0 where they are 1-based – or some value to be interpreted as Boolean FALSE. This can be accomplished as a special case of Find , with a string of one character; but it may be simpler or more efficient in many languages to locate just one character. Also, in many languages, characters and strings are different types, so it is convenient to have such a function.
Related	find

Format	Languages	If not found
char in string(char, pos, ''string[startpos:]'')	ALGOL 68	returns : or, and position in .
instr(''string'', any ''char''«,''startpos''») (char, can contain more them one char, in which case the position of the first appearance of any of them is returned.)	FreeBASIC	returns 0
strchr(''string'',''char'')	C, C++ ([[character (computing)|char]] [[Pointer (computer programming)|*]] only, returns pointer to character)	returns
std.string.find(''string'', ''dchar'')	D	returns −1
''string''.find(''char''«,''startpos''»)	C++ (STL)	returns
pos(''string'', ''char''«, ''startpos''»)	Seed7	returns 0
strings.IndexRune(''string'',''char'')	Go	returns −1
''string''.indexOf(''char''«,''startpos''»)	Java, JavaScript	returns −1
''string''.IndexOf(''char''«,''startpos''«, ''charcount''»»)	VB .NET, C#, Windows PowerShell, F#	returns −1
(position ''char'' ''string'')	Common Lisp	returns
(char-index ''char'' ''string'')	ISLISP	returns
List.elemIndex ''char'' ''string''	Haskell (returns Just ''index'')	returns
String.index ''string'' ''char''	OCaml	raises
position = SCAN (''string'', ''set'' «, ''back''» «, ''kind''») position = VERIFY (''string'', ''set'' «, ''back''» «, ''kind''»){{ref|Fortran find|[a]}}	Fortran	returns zero
''string'' indexOf: ''char'' ifAbsent: aBlock ''string'' indexOf: ''char'' ''string'' includes: ''char''	Smalltalk	evaluate aBlock which is a BlockClosure (or any object understanding value) returns 0 returns true or false
index(''string'', ''char'', ''startpos'')	PL/I^[16]	returns 0 (positions start at 1)
''string''.index(?''char'')	Ruby	returns
strpos(''string'',''char'',''startpos'')	PHP	returns
''string''.indexOf(''char''«,''startpos''«, ''charcount''»»)	Cobra	returns −1
''string''⍳''char''	APL	returns 1 + the last position in string
''string''.find(''substring'')	Rust	returns

// Examples in C#"Hello mate".IndexOf('e'); // returns 1"word".IndexOf('z') // returns -1

Examples in Common Lisp(position #\e "Hello mate") ; returns 1(position #\z "word") ; returns NIL Given a set of characters, SCAN returns the position of the first character found,^[17] while VERIFY returns the position of the first character that does not belong to the set.^[18]

Format

See also: printf format string.

Definition	format(''formatstring'', ''items'') returns string
Description	Returns the formatted string representation of one or more items.

Format	Languages	Format string syntax
associate(''file'', ''string''); [[putf]](''file'', ''$formatstring$'', ''items'')	ALGOL 68	ALGOL
Format(''item'', ''formatstring'')	VB
[[sprintf]](''formatstring'', ''items'')	Perl, PHP, Raku, Ruby	C
item.fmt(''formatstring'')	Raku	C
io_lib:format(''formatstring'', ''items'')	Erlang
[[sprintf]](''outputstring'', ''formatstring'', ''items'')	C	C
std::format(''formatstring'', ''items'')	C++ (C++20)	Python
std.string.format(''formatstring'', ''items'')	D	C
Format(''formatstring'', ''items'')	Object Pascal (Delphi)
fmt.Sprintf(''formatstring'', ''items'')	Go	C
[[printf (Unix)|printf]] ''formatstring'' ''items''	Unix	C
''formatstring'' % (''items'')	Python, Ruby	C
''formatstring''.format(''items'')	Python	.NET
f''formatstring''	Python 3
Printf.sprintf ''formatstring''^[19] ''items''	OCaml, F#	C
Text.Printf.printf ''formatstring'' ''items''	Haskell (GHC)	C
''formatstring'' printf: ''items''	Smalltalk	C
String.format(''formatstring'', ''items'')	Java	C
String.Format(''formatstring'', ''items'')	VB .NET, C#, F#	.NET
(format ''formatstring'' ''items'')	Scheme (SRFI 28)	Lisp
([[Format (Common Lisp)|format]] nil ''formatstring'' ''items'')	Common Lisp	Lisp
(format ''formatstring'' ''items'')	Clojure	Lisp
''formatstring'' -f ''items''	Windows PowerShell	.NET
[NSString stringWithFormat:''formatstring'', ''items'']	Objective-C (NSString * only)	C
String(format:''formatstring'', ''items'')	Swift (Foundation)	C
string.format(''formatstring'', ''items'') (''formatstring''):format(''items'')	Lua	C
WRITE (''outputstring'', ''formatstring'') ''items''	Fortran	Fortran
put string(''string'') edit(''items'')(''format'')	PL/I	PL/I (similar to Fortran)
String.format(''formatstring'', ''items'')	Cobra	.NET
format ''formatstring items''	Tcl	C
''formatnumbers'' ⍕ ''items'' ''formatstring'' ⎕FMT ''items''	APL	APL
format!(''formatstring'', ''items'')	Rust^[20]	Python

// Example in C#String.Format("My costs ", "pen", 19.99); // returns "My pen costs $19.99"

// Example in Object Pascal (Delphi)Format('My %s costs $%2f', ['pen', 19.99]); // returns "My pen costs $19.99"

// Example in JavaString.format("My %s costs $%2f", "pen", 19.99); // returns "My pen costs $19.99"

1. Examples in Raku

sprintf "My %s costs \$%.2f", "pen", 19.99; # returns "My pen costs $19.99"1.fmt("%04d"); # returns "0001"

1. Example in Python

"My %s costs $%.2f" % ("pen", 19.99); # returns "My pen costs $19.99""My costs $".format("pen", 19.99); # returns "My pen costs $19.99"

1. Example in Python 3.6+

pen = "pen"f"My costs " #returns "My pen costs 19.99"

Example in Scheme(format "My ~a costs $~1,2F" "pen" 19.99) ; returns "My pen costs $19.99"

/* example in PL/I */put string(some_string) edit('My ', 'pen', ' costs', 19.99)(a,a,a,p'$$$V.99')/* returns "My pen costs $19.99" */

Inequality

Tests if two strings are not equal. See also

1. Equality

.

Format	Languages
''string<sub>1</sub>'' '''ne''' ''string<sub>2</sub>'' ''string<sub>1</sub>'' NE ''string<sub>2</sub>''	ALGOL 68 – note: the operator "ne" is literally in bold type-font.
''string<sub>1</sub>'' /= ''string<sub>2</sub>''	ALGOL 68, Ada, Erlang, Fortran, Haskell
''string<sub>1</sub>'' <> ''string<sub>2</sub>''	BASIC, VB, VB .NET, Pascal, Object Pascal (Delphi), OCaml, PHP, Seed7, Standard ML, F#, COBOL, Cobra, Python 2 (deprecated)
''string<sub>1</sub>'' # ''string<sub>2</sub>''	BASIC (some implementations)
''string<sub>1</sub>'' ne ''string<sub>2</sub>''	Perl, Raku
(string<> ''string<sub>1</sub>'' ''string<sub>2</sub>'')	Scheme (SRFI 13)
(string/= ''string<sub>1</sub>'' ''string<sub>2</sub>'')	Common Lisp
(string/= ''string<sub>1</sub>'' ''string<sub>2</sub>'')	ISLISP
(not= ''string<sub>1</sub>'' ''string<sub>2</sub>'')	Clojure
''string<sub>1</sub>'' != ''string<sub>2</sub>''	C++ (STL), C#, Go, JavaScript (not similar), PHP (not similar), Python, Ruby, Rust, Swift, D, Mathematica
''string<sub>1</sub>'' !== ''string<sub>2</sub>''	JavaScript, PHP
''string<sub>1</sub>'' \= ''string<sub>2</sub>''	Rexx
''string<sub>1</sub>'' ¬= ''string<sub>2</sub>''	PL/I
test ''string<sub>1</sub>'' != ''string<sub>2</sub>'' [ ''string<sub>1</sub>'' != ''string<sub>2</sub>'' ]	Bourne Shell
''string<sub>1</sub>'' -ne ''string<sub>2</sub>'' -not [string]::Equals(''string<sub>1</sub>'', ''string<sub>2</sub>'')	Windows PowerShell
''string<sub>1</sub>'' ~= ''string<sub>2</sub>''	Lua, Smalltalk
''string<sub>1</sub>'' ≢ ''string<sub>2</sub>''	APL
''string<sub>1</sub>''.ne(''string<sub>2</sub>'')	Rust

// Example in C#"hello" != "world" // returns true

' Example in Visual Basic"hello" <> "world" ' returns true

Example in Clojure(not= "hello" "world") ; ⇒ true

1. Example in Perl 5

'hello' ne 'world' # returns 1

1. Example in Raku

'hello' ne 'world' # returns True

1. Example in Windows PowerShell

"hello" -ne "world" # returns true

index

see

1. Find

indexof

see

1. Find

instr

see

1. Find

instrrev

see

1. rfind

join

Definition	join(''separator'', ''list_of_strings'') returns a list of strings joined with a separator
Description	Joins the list of strings into a new string, with the separator string between each of the substrings. Opposite of split.
Related	sprintf

Format	Languages
std.string.join(''array_of_strings'', ''separator'')	D
string:join(''list_of_strings'', ''separator'')	Erlang
join(''separator'', ''list_of_strings'')	Perl, PHP, Raku
implode(''separator'', ''array_of_strings'')	PHP
''separator''.join(''sequence_of_strings'')	Python, Swift 1.x
''array_of_strings''.join(''separator'')	Ruby, JavaScript, Raku, Rust^[21]
(string-join ''array_of_strings'' ''separator'')	Scheme (SRFI 13)
([[Format (Common Lisp)|format]] nil "~{~a~^''separator''~}" ''array_of_strings'')	Common Lisp
(clojure.string/join ''separator'' ''list_of_strings'') (apply str (interpose ''separator'' ''list_of_strings''))	Clojure
strings.Join(''array_of_strings'', ''separator'')	Go
join(''array_of_strings'', ''separator'')	Seed7
String.concat ''separator'' ''list_of_strings''	OCaml
String.concatWith ''separator'' ''list_of_strings''	Standard ML
Data.List.intercalate ''separator'' ''list_of_strings''	Haskell (GHC 6.8+)
Join(''array_of_strings'', ''separator'')	VB
String.Join(''separator'', ''array_of_strings'')	VB .NET, C#, F#
String.join(''separator'', ''array_of_strings'')	Java 8+
&{$OFS=''$separator''; "''$array_of_strings''"} ''array_of_strings'' -join ''separator''	Windows PowerShell
[''array_of_strings'' componentsJoinedByString:''separator'']	Objective-C (NSString * only)
table.concat(''table_of_strings'', ''separator'')	Lua
<nowiki>{|String streamContents: [ :stream |</nowiki> ''collectionOfAnything'' asStringOn: stream delimiter: ''separator'' <nowiki>]</nowiki> ''collectionOfAnything'' joinUsing: ''separator''|Smalltalk (Squeak, Pharo)|-| ''array_of_strings''.join(''separator''«, ''final_separator''»)|Cobra|-| ''sequence_of_strings''.joinWithSeparator(''separator'')|Swift 2.x|-| 1↓∊''separator'',¨''list_of_strings''|APL|} // Example in C#String.Join("-",) // "a-b-c" " Example in Smalltalk " ('a' 'b' 'c') joinUsing: '-' " 'a-b-c' " Example in Perl 5 join('-', ('a', 'b', 'c')); # 'a-b-c' Example in Raku .join('-'); # 'a-b-c' Example in Python "-".join(["a", "b", "c"]) # 'a-b-c' Example in Ruby ["a", "b", "c"].join("-") # 'a-b-c' Example in Scheme(use-modules (srfi srfi-13))(string-join '("a" "b" "c") "-") ; "a-b-c" lastindexof see rfind left Definition left(''string'',''n'') returns string Description Returns the left n part of a string. If n is greater than the length of the string then most implementations return the whole string (exceptions exist – see code examples). Note that for variable-length encodings such as UTF-8, UTF-16 or Shift-JIS, it can be necessary to remove string positions at the end, in order to avoid invalid strings. Format Languages string (string'First .. string'First + ''n'' - 1) Ada substr(''string'', 0, ''n'') AWK (changes string), Perl, PHP, Raku LEFT$(''string'',''n'') BASIC, VB left(''string'',''n'') VB, FreeBASIC, Ingres, Pick Basic strncpy(''string2'', ''string'', ''n'') C standard library ''string''.substr(0,''n'') C++ (STL), Raku [''string'' substringToIndex:''n''] Objective-C (NSString * only) (apply str (take ''n'' ''string'')) Clojure ''string''[0 .. ''n''] D^[22] string:substr(''string'', ''start'', ''length'') Erlang (subseq ''string'' 0 ''n'') Common Lisp ''string''[:''n''] Cobra, Go, Python left(''string'',''n'' «,''padchar''») Rexx, Erlang ''string''[0, ''n''] ''string''[0..''n'' - 1] Ruby ''string''[1, ''n''] Pick Basic ''string''[ .. ''n''] Seed7 ''string''.Substring(0,''n'') VB .NET, C#, Windows PowerShell, F# leftstr(''string'', ''n'') Pascal, Object Pascal (Delphi) ''copy'' (''string'',1,''n'') Turbo Pascal ''string''.substring(0,''n'') Java,^[23] JavaScript (string-take ''string'' ''n'') Scheme (SRFI 13) take ''n'' ''string'' Haskell String.extract (''string'', ''n'', NONE) Standard ML String.sub ''string'' 0 ''n'' OCaml^[24] ''string''.[..''n''] F# string.sub(''string'', 1, ''n'') (''string''):sub(1, ''n'') Lua ''string'' first: ''n'' Smalltalk (Squeak, Pharo) ''string''(:''n'') Fortran StringTake[''string'', ''n''] Mathematica^[25] ''string'' («FUNCTION» LENGTH(''string'') - ''n'':''n'') COBOL ''string''.substring(0, ''n'') Cobra ''n''↑''string''. APL ''string''[0..n] ''string''[..n] ''string''.get(0..n) ''string''.get(..n) Rust^[26] Example in Raku "Hello, there!".substr(0, 6); # returns "Hello," /* Examples in Rexx */left("abcde", 3) /* returns "abc" */left("abcde", 8) /* returns "abcde " */left("abcde", 8, "*") /* returns "abcde***" */ Examples in Scheme(use-modules (srfi srfi-13))(string-take "abcde", 3) ; returns "abc"(string-take "abcde", 8) ; error ' Examples in Visual BasicLeft("sandroguidi", 3) ' returns "san"Left("sandroguidi", 100) ' returns "sandroguidi" len see length length Definition length(''string'') returns an integer number Description Returns the length of a string (not counting the null terminator or any other of the string's internal structural information). An empty string returns a length of 0. Format Returns Languages string'Length Ada UPB string ALGOL 68 echo "${#''string_param''}" Bash length(''string'') Ingres, Perl 5, Pascal, Object Pascal (Delphi), Rexx, Seed7, SQL, PL/I len(''string'') BASIC, FreeBASIC, Python, Go, Pick Basic length(''string''), string:len(''string'') Erlang Len(''string'') VB, Pick Basic ''string''.Length Number of UTF-16 code units VB .NET, C#, Windows PowerShell, F# chars(''string'') ''string''.chars Number of graphemes (NFG) Raku codes(''string'') ''string''.codes Number of Unicode code points Raku ''string''.size OR ''string''.length Number of bytes^[27] Ruby [[strlen]](''string'') Number of bytes C, PHP ''string''.length C++ (STL) ''string''.length Cobra, D, JavaScript ''string''.length Number of UTF-16 code units Java (string-length ''string'') Scheme (length ''string'') Common Lisp, ISLISP (count ''string'') Clojure String.length ''string'' OCaml size ''string'' Standard ML length ''string'' Number of Unicode code points Haskell ''string''.length Number of UTF-16 code units Objective-C (NSString * only) ''string''.characters.count Number of characters Swift (2.x) count(''string'') Number of characters Swift (1.2) countElements(''string'') Number of characters Swift (1.0–1.1) string.len(''string'') (''string''):len #''string'' Lua ''string'' size Smalltalk LEN(''string'') LEN_TRIM(''string'') Fortran StringLength[''string''] Mathematica «FUNCTION» LENGTH(''string'') or«FUNCTION» BYTE-LENGTH(''string'') number of characters and number of bytes, respectively COBOL string length ''string'' a decimal string giving the number of characters Tcl ≢ ''string'' APL ''string''.len Number of bytes Rust^[28] ''string''.chars.count Number of Unicode code points Rust^[29] // Examples in C#"hello".Length; // returns 5"".Length; // returns 0 Examples in Erlang string:len("hello"). % returns 5string:len(""). % returns 0 Examples in Perl 5 length("hello"); # returns 5length(""); # returns 0 Examples in Raku "️‍".chars; chars "️‍"; # both return 1"️‍".codes; codes "️‍"; # both return 4"".chars; chars ""; # both return 0"".codes; codes ""; # both return 0 ' Examples in Visual BasicLen("hello") ' returns 5Len("") ' returns 0 //Examples in Objective-C[@"hello" Length] //returns 5[@"" Length] //returns 0 -- Examples in Lua("hello"):len -- returns 5 "" -- returns 0 locate see Find Lowercase Definition lowercase(''string'') returns string Description Returns the string in lower case. Format Languages LCase(''string'') VB lcase(''string'') FreeBASIC lc(''string'') Perl, Raku ''string''.lc Raku tolower(''char'') C^[30] std.string.toLower(''string'') D transform(''string''.begin, ''string''.end, ''result''.begin, ::tolower)^[31] C++^[32] lowercase(''string'') Object Pascal (Delphi) strtolower(''string'') PHP lower(''string'') Seed7 ${''string_param'',,} Bash [[echo (command)|echo]] "string" <nowiki>|</nowiki> [[tr (program)|tr]] 'A-Z' 'a-z'|Unix|-| ''string''.lower|Python|-| downcase(''string'')|Pick Basic|-| ''string''.downcase|Ruby^[33] |-| strings.ToLower(''string'')|Go|-| (string-downcase ''string'')|Scheme (R6RS), Common Lisp|-| (lower-case ''string'')|Clojure|-| String.lowercase ''string''|OCaml|-| String.map Char.toLower ''string''|Standard ML|-| map Char.toLower ''string''|Haskell|-| ''string''.toLowerCase|Java, JavaScript|-| to_lower(''string'')|Erlang|-| ''string''.ToLower|VB .NET, C#, Windows PowerShell, F#|-| ''string''.lowercaseString|Objective-C (NSString * only), Swift (Foundation)|-| string.lower(''string'') (''string''):lower|Lua|-| ''string'' asLowercase|Smalltalk|-| LOWER(''string'')|SQL|-| lowercase(''string'')|PL/I|-| ToLowerCase[''string'']|Mathematica|-| «FUNCTION» LOWER-CASE(''string'')|COBOL|-| ''string''.toLower|Cobra|-| string tolower ''string''|Tcl|-| ''string''.to_lowercase| Rust^[34] |} // Example in C#"Wiki means fast?".ToLower; // "wiki means fast?" Example in Scheme(use-modules (srfi srfi-13))(string-downcase "Wiki means fast?") ; "wiki means fast?" /* Example in C */ include include int main(void) Example in Raku "Wiki means fast?".lc; # "wiki means fast?" mid see substring partition Definition .partition(separator) returns the sub-string before the separator; the separator; then the sub-string after the separator. Description Splits the given string by the separator and returns the three substrings that together make the original. Format Languages Comments ''string''.partition(''separator'') Python, Ruby(1.9+) lists:partition(''pred'', ''string'') Erlang split /(''separator'')/, ''string'', 2 Perl 5 split ''separator'', ''string'', 2 ''string''.split(''separator'', 2) Raku Separator does not have to be a regular expression Examples in Python "Spam eggs spam spam and ham".partition('spam') # ('Spam eggs ', 'spam', ' spam and ham')"Spam eggs spam spam and ham".partition('X') # ('Spam eggs spam spam and ham', "", "") Examples in Perl 5 / Raku split /(spam)/, 'Spam eggs spam spam and ham',2; # ('Spam eggs ', 'spam', ' spam and ham');split /(X)/, 'Spam eggs spam spam and ham',2; # ('Spam eggs spam spam and ham'); replace Definition replace(''string'', ''find'', ''replace'') returns string Description Returns a string with find occurrences changed to replace. Format Languages changestr(''find'', ''string'', ''replace'') Rexx std.string.replace(''string'', ''find'', ''replace'') D Replace(''string'', ''find'', ''replace'') VB replace(''string'', ''find'', ''replace'') Seed7 change(''string'', ''find'', ''replace'') Pick Basic ''string''.Replace(''find'', ''replace'') C#, F#, VB .NET str_replace(''find'', ''replace'', ''string'') PHP re:replace(''string'', ''find'', ''replace'', «{return, list}») Erlang ''string''.replace(''find'', ''replace'') Cobra, Java (1.5+), Python, Rust^[35] ''string''.replaceAll(''find_regex'', ''replace'')<ref name="regex" /> Java ''string''.gsub(''find'', ''replace'') Ruby ''string'' =~ s/''find_regex''/''replace''/g<ref name="regex">The "find" string in this construct is interpreted as a [[regular expression]]. Certain characters have special meaning in regular expressions. If you want to find a string literally, you need to quote the special characters.</ref> Perl 5 ''string''.subst(''find'', ''replace'', :g) Raku ''string''.replace(''find'', ''replace'', "g") <ref>third parameter is non-standard</ref> ''string''.replace(/''find_regex''/g, ''replace'')<ref name="regex" /> JavaScript [[echo (command)|echo]] "''string''" <nowiki>|</nowiki> [[sed]] 's/''find_regex''/''replace''/g'<ref name="regex" />|Unix|-| ${''string_param''//''find_pattern''/''replace''}|Bash|-| ''string''.replace(''find'', ''replace'') ''string'' -replace ''find_regex'', ''replace''<ref name="regex" />|Windows PowerShell|-| Str.global_replace (Str.regexp_string ''find'') ''replace'' ''string''|OCaml|-| [''string'' stringByReplacingOccurrencesOfString:''find'' withString:''replace'']|Objective-C (NSString * only)|-| ''string''.stringByReplacingOccurrencesOfString(''find'', withString:''replace'')|Swift (Foundation)|-| string.gsub(''string'', ''find'', ''replace'') (''string''):gsub(''find'', ''replace'')|Lua|-| ''string'' copyReplaceAll: ''find'' with: ''replace''|Smalltalk (Squeak, Pharo)|-| string map {''find'' ''replace''} ''string''|Tcl|-| StringReplace[''string'', ''find'' -> ''replace'']|Mathematica|-| strings.Replace(''string'', ''find'', ''replace'', -1)| Go|-| INSPECT ''string'' REPLACING ALL/LEADING/FIRST ''find'' BY ''replace''| COBOL|-| ''find_regex'' ⎕R ''replace_regex'' ⊢ ''string''| APL|} // Examples in C#"effffff".Replace("f", "jump"); // returns "ejumpjumpjumpjumpjumpjump""blah".Replace("z", "y"); // returns "blah" // Examples in Java"effffff".replace("f", "jump"); // returns "ejumpjumpjumpjumpjumpjump""effffff".replaceAll("f*", "jump"); // returns "ejump" // Examples in Raku"effffff".subst("f", "jump", :g); # returns "ejumpjumpjumpjumpjumpjump""blah".subst("z", "y", :g); # returns "blah" ' Examples in Visual BasicReplace("effffff", "f", "jump") ' returns "ejumpjumpjumpjumpjumpjump"Replace("blah", "z", "y") ' returns "blah" Examples in Windows PowerShell "effffff" -replace "f", "jump" # returns "ejumpjumpjumpjumpjumpjump""effffff" -replace "f*", "jump" # returns "ejump" reverse Definition reverse(''string'') Description Reverses the order of the characters in the string. Format Languages reverse ''string'' Perl 5, Haskell flip ''string'' ''string''.flip Raku lists:reverse(''string'') Erlang strrev(''string'') PHP ''string''[::-1] Python (string-reverse ''string'') Scheme (SRFI 13) (reverse ''string'') Common Lisp ''string''.reverse Ruby, D (modifies string) new StringBuilder(''string'').reverse.toString Java std::reverse(''string''.begin, ''string''.end); C++ ([[std::string]] only, modifies string) StrReverse(''string'') VB ''string''.Reverse VB .NET, C# implode (rev (explode ''string'')) Standard ML ''string''.split("").reverse.join("") JavaScript string.reverse(''string'') (''string''):reverse Lua ''string'' reverse Smalltalk StringReverse[''string''] Mathematica reverse(''string'') PL/I «FUNCTION» REVERSE(''string'') COBOL ''string''.toCharArray.toList.reversed.join Cobra String(''string''.characters.reverse) Swift (2.x) String(reverse(''string'')) Swift (1.2) string reverse ''string'' Tcl ⌽''string'' APL ''string''.chars.rev.collect::<String> Rust^[36] echo ''string'' <nowiki>|</nowiki> rev| Unix|} " Example in Smalltalk "'hello' reversed " returns 'olleh' " Example in Perl 5 reverse "hello" # returns "olleh" Example in Raku "hello".flip # returns "olleh" Example in Python "hello"[::-1] # returns "olleh" Example in Scheme(use-modules (srfi srfi-13))(string-reverse "hello") ; returns "olleh" rfind Definition rfind(''string'',''substring'') returns integer Description Returns the position of the start of the last occurrence of substring in string. If the substring is not found most of these routines return an invalid index value – -1 where indexes are 0-based, 0 where they are 1-based – or some value to be interpreted as Boolean FALSE. Related instr Format Languages If not found InStrRev(«''startpos'',» ''string'',''substring'') VB returns 0 instrrev(«''startpos'',» ''string'',''substring'') FreeBASIC returns 0 rindex(''string'',''substring''«,''startpos''») Perl 5 returns −1 rindex(''string'',''substring''«,''startpos''») ''string''.rindex(''substring''«,''startpos''») Raku returns strrpos(''string'',''substring''«,''startpos''») PHP returns ''string''.rfind(''substring''«,''startpos''») C++ (STL) returns std.string.rfind(''string'', ''substring'') D returns −1 ''string''.rfind(''substring''«,''startpos''«, ''endpos''»») Python returns −1 ''string''.rindex(''substring''«,''startpos''«, ''endpos''»») raises rpos(''string'', ''substring''«,''startpos''») Seed7 returns 0 ''string''.rindex(''substring''«,''startpos''») Ruby returns strings.LastIndex(''string'', ''substring'') Go returns −1 ''string''.lastIndexOf(''substring''«,''startpos''») Java, JavaScript returns −1 ''string''.LastIndexOf(''substring''«,''startpos''«, ''charcount''»») VB .NET, C#, Windows PowerShell, F# returns −1 (search ''substring'' ''string'' :from-end t) Common Lisp returns [''string'' rangeOfString:''substring'' options:NSBackwardsSearch].location Objective-C (NSString * only) returns Str.search_backward (Str.regexp_string ''substring'') ''string'' (Str.length ''string'' - 1) OCaml raises string.match(''string'', '.*'..''substring'') ''string'':match('.*'..''substring'') Lua returns Ada.Strings.Unbounded.Index(Source => ''string'', Pattern => ''substring'', Going => Ada.Strings.Backward) Ada returns 0 ''string''.lastIndexOf(''substring''«,''startpos''«, ''charcount''»») Cobra returns −1 ''string'' lastIndexOfString:''substring'' Smalltalk returns 0 string last ''substring string startpos'' Tcl returns −1 (⌽<\⌽''substring''⍷'string')⍳1 APL returns −1 ''string''.rfind(''substring'') Rust^[37] returns Examples in Common Lisp(search "e" "Hello mate" :from-end t) ; returns 9(search "z" "word" :from-end t) ; returns NIL // Examples in C#"Hello mate".LastIndexOf("e"); // returns 9"Hello mate".LastIndexOf("e", 4); // returns 1"word".LastIndexOf("z"); // returns -1 Examples in Perl 5 rindex("Hello mate", "e"); # returns 9rindex("Hello mate", "e", 4); # returns 1rindex("word", "z"); # returns -1 Examples in Raku "Hello mate".rindex("e"); # returns 9"Hello mate".rindex("e", 4); # returns 1"word".rindex('z'); # returns Nil ' Examples in Visual BasicInStrRev("Hello mate", "e") ' returns 10InStrRev(5, "Hello mate", "e") ' returns 2InStrRev("word", "z") ' returns 0 right Definition right(''string'',''n'') returns string Description Returns the right n part of a string. If n is greater than the length of the string then most implementations return the whole string (exceptions exist – see code examples). Format Languages string (string'Last - ''n'' + 1 .. string'Last) Ada Right(''string'',''n'') VB RIGHT$(''string'',''n'') BASIC right(''string'',''n'') FreeBASIC, Ingres, Pick Basic strcpy(''string2'', ''string''+''n'') (n must not be greater than the length of string) C ''string''.Substring(''string''.Length-''n'') C# ''string''[len(''string'')-''n'':] Go ''string''.substring(''string''.length-''n'') Java ''string''.slice(-''n'') JavaScript^[38] right(''string'',''n'' «,''padchar''») Rexx, Erlang substr(''string'',-''n'') Perl 5, PHP substr(''string'',*-''n'') ''string''.substr(*-''n'') Raku ''string''[-''n'':] Cobra, Python ${''string_param'': -''n''} (note the space after the colon) Bash ''string''[''n''] Pick Basic (string-take-right ''string'' ''n'') Scheme (SRFI 13) ''string''[-''n''..-1] Ruby ''string''[$-''n'' .. $] D^[39] String.sub ''string'' (String.length ''string'' - ''n'') ''n'' OCaml string.sub(''string'', -''n'') (''string''):sub(-''n'') Lua ''string'' last: ''n'' Smalltalk (Squeak, Pharo) StringTake[''string'', -''n''] Mathematica ''string'' (1:''n'') COBOL ''¯n''↑''string''. APL ''string''[n..] ''string''.get(n..) Rust // Examples in Java; extract rightmost 4 charactersString str = "CarDoor";str.substring(str.length-4); // returns 'Door' Examples in Raku "abcde".substr(*-3); # returns "cde""abcde".substr(*-8); # 'out of range' error /* Examples in Rexx */right("abcde", 3) /* returns "cde" */right("abcde", 8) /* returns " abcde" */right("abcde", 8, "*") /* returns "***abcde" */ Examples in Scheme(use-modules (srfi srfi-13))(string-take-right "abcde", 3) ; returns "cde"(string-take-right "abcde", 8) ; error ' Examples in Visual BasicRight("sandroguidi", 3) ' returns "idi"Right("sandroguidi", 100) ' returns "sandroguidi" rpartition Definition .rpartition(separator) Searches for the separator from right-to-left within the string then returns the sub-string before the separator; the separator; then the sub-string after the separator. Description Splits the given string by the right-most separator and returns the three substrings that together make the original. Examples in Python "Spam eggs spam spam and ham".rpartition('spam') ### ('Spam eggs spam ', 'spam', ' and ham')"Spam eggs spam spam and ham".rpartition('X') ### ("", "", 'Spam eggs spam spam and ham') slice see substring split Definition .split(separator[, ''limit'']) splits a string on separator, optionally only up to a limited number of substrings Description Splits the given string by occurrences of the separator (itself a string) and returns a list (or array) of the substrings. If limit is given, after limit – 1 separators have been read, the rest of the string is made into the last substring, regardless of whether it has any separators in it. The Scheme and Erlang implementations are similar but differ in several ways. JavaScript differs also in that it cuts, it does not put the rest of the string into the last element. See the example here. The Cobra implementation will default to whitespace. Opposite of join. Format Languages split(/''separator''/, ''string''«, ''limit''») Perl 5 split(''separator'', ''string''«, ''limit''») ''string''.split(''separator'', «''limit''») Raku explode(''separator'', ''string''«, ''limit''») PHP ''string''.split(''separator''«, ''limit''-1») Python ''string''.split(''separator''«, ''limit''») JavaScript, Java, Ruby string:tokens(''string'', ''sepchars'') Erlang strings.Split(''string'', ''separator'') strings.SplitN(''string'', ''separator'', ''limit'') Go (string-tokenize ''string''« ''charset''« ''start''« ''end''»»») Scheme (SRFI 13) Split(''string'', ''sepchars''«, ''limit''») VB ''string''.Split(''sepchars''«, ''limit''«, ''options''»») VB .NET, C#, F# ''string'' -split ''separator''«, ''limit''«, ''options''»» Windows PowerShell Str.split (Str.regexp_string ''separator'') ''string'' OCaml std.string.split(''string'', ''separator'') D [''string'' componentsSeparatedByString:''separator''] Objective-C (NSString * only) ''string''.componentsSeparatedByString(''separator'') Swift (Foundation) TStringList.Delimiter, TStringList.DelimitedText Object Pascal StringSplit[''string'', ''separator''«, ''limit''»] Mathematica ''string''.split«(''sepchars''«, ''limit''«, ''options''»»)» Cobra split ''string separator'' Tcl (''separator''≠''string'')⊂''string'' in APL2 ''separator''(≠⊆⊢)''string'' in Dyalog APL 16.0 APL ''string''.split(''separator'')''string''.split(''limit'', ''separator'') Rust^[40] // Example in C#"abc,defgh,ijk".Split(','); // "abc,defgh;ijk".Split(',', ';'); // % Example in Erlangstring:tokens("abc;defgh;ijk", ";"). % ["abc", "defgh", "ijk"] // Examples in Java"abc,defgh,ijk".split(","); // "abc,defgh;ijk".split(",|;"); // var lStrings: TStringList; lStr: string;begin lStrings := TStringList.Create; lStrings.Delimiter := ','; lStrings.DelimitedText := 'abc,defgh,ijk'; lStr := lStrings.Strings[0]; // 'abc' lStr := lStrings.Strings[1]; // 'defgh' lStr := lStrings.Strings[2]; // 'ijk'end; Examples in Perl 5 split(/spam/, 'Spam eggs spam spam and ham'); # ('Spam eggs ', ' ', ' and ham')split(/X/, 'Spam eggs spam spam and ham'); # ('Spam eggs spam spam and ham') Examples in Raku 'Spam eggs spam spam and ham'.split(/spam/); # (Spam eggs and ham)split(/X/, 'Spam eggs spam spam and ham'); # (Spam eggs spam spam and ham) sprintf see Format strip see trim strcmp see Compare (integer result) substring Definition substring(''string'', ''startpos'', ''endpos'') returns string substr(''string'', ''startpos'', ''numChars'') returns string Description Returns a substring of string between starting at startpos and endpos, or starting at startpos of length numChars. The resulting string is truncated if there are fewer than numChars characters beyond the starting point. endpos represents the index after the last character in the substring. Note that for variable-length encodings such as UTF-8, UTF-16 or Shift-JIS, it can be necessary to remove string positions at the end, in order to avoid invalid strings. Format Languages string[''startpos'':''endpos''] ALGOL 68 (changes base index) string (''startpos'' .. ''endpos'') Ada (changes base index) Mid(''string'', ''startpos'', ''numChars'') VB mid(''string'', ''startpos'', ''numChars'') FreeBASIC ''string''[''startpos''+(⍳''numChars'')-~⎕IO] APL MID$(''string'', ''startpos'', ''numChars'') BASIC substr(''string'', ''startpos'', ''numChars'') AWK (changes string), Perl 5, PHP substr(''string'', ''startpos'', ''numChars'') ''string''.substr(''startpos'', ''numChars'') Raku substr(''string'', ''startpos'' «,''numChars'', ''padChar''») Rexx ''string''[''startpos'':''endpos''] Cobra, Python, Go ''string''[''startpos'', ''numChars''] Pick Basic ''string''[''startpos'', ''numChars''] ''string''[''startpos'' .. ''endpos''-1] ''string''[''startpos'' ... ''endpos''] Ruby ''string''[''startpos'' .. ''endpos''] ''string''[''startpos'' len ''numChars''] Seed7 ''string''.slice(''startpos''«, ''endpos''») JavaScript ''string''.substr(''startpos''«, ''numChars''») C++ (STL), JavaScript ''string''.Substring(''startpos'', ''numChars'') VB .NET, C#, Windows PowerShell, F# ''string''.substring(''startpos''«, ''endpos''») Java, JavaScript copy(''string'', ''startpos'', ''numChars'') Object Pascal (Delphi) (substring ''string'' ''startpos'' ''endpos'') Scheme (subseq ''string'' ''startpos'' ''endpos'') Common Lisp (subseq ''string'' ''startpos'' ''endpos'') ISLISP String.sub ''string'' ''startpos'' ''numChars'' OCaml substring (''string'', ''startpos'', ''numChars'') Standard ML string:sub_string(''string'', ''startpos'', ''endpos'') string:substr(''string'', ''startpos'', ''numChars'') Erlang strncpy(''result'', ''string'' + ''startpos'', ''numChars''); C ''string''[''startpos'' .. ''endpos''+1] D take ''numChars'' $ drop ''startpos'' ''string'' Haskell [''string'' substringWithRange:NSMakeRange(''startpos'', ''numChars'')] Objective-C (NSString * only) ''string''.[''startpos''..''endpos''] F# string.sub(''string'', ''startpos'', ''endpos'') (''string''):sub(''startpos'', ''endpos'') Lua ''string'' copyFrom: ''startpos'' to: ''endpos'' Smalltalk ''string''(''startpos'':''endpos'') Fortran SUBSTRING(''string'' FROM ''startpos'' «FOR ''numChars''») SQL StringTake[''string'', {''startpos'', ''endpos''}] Mathematica ''string'' (''startpos'':''numChars'') COBOL ${''string_param'':''startpos'':''numChars''} Bash string range string startpos endpos Tcl ''string''[''startpos''..''endpos''] ''string''.get(''startpos''..''endpos'') Rust // Examples in C#"abc".Substring(1, 1): // returns "b""abc".Substring(1, 2); // returns "bc""abc".Substring(1, 6); // error Examples in Common Lisp(subseq "abc" 1 2) ; returns "b"(subseq "abc" 2) ; returns "c" % Examples in Erlangstring:substr("abc", 2, 1). % returns "b"string:substr("abc", 2). % returns "bc" Examples in Perl 5 substr("abc", 1, 1); # returns "b"substr("abc", 1); # returns "bc" Examples in Raku "abc".substr(1, 1); # returns "b""abc".substr(1); # returns "bc" Examples in Python "abc"[1:2] # returns "b""abc"[1:3] # returns "bc" /* Examples in Rexx */substr("abc", 2, 1) /* returns "b" */substr("abc", 2) /* returns "bc" */substr("abc", 2, 6) /* returns "bc " */substr("abc", 2, 6, "*") /* returns "bc****" */ Uppercase Definition uppercase(''string'') returns string Description Returns the string in upper case. Format Languages UCase(''string'') VB ucase(''string'') FreeBASIC toupper(''string'') AWK (changes string) uc(''string'') Perl, Raku ''string''.uc Raku toupper(''char'') C (operates on one character) for(size_t i = 0, len = strlen(''string''); i&lt; len; i++) ''string''[i] = toupper(''string''[i]); for (char *c = ''string''; *c != '\0'; c++) *c = toupper(*c); C (string / char array) std.string.toUpper(''string'') D transform(''string''.begin, ''string''.end, ''result''.begin, toupper)<ref name="cpptransform" /> C++^[41] uppercase(''string'') Object Pascal (Delphi) upcase(''char'') Object Pascal (Delphi) (operates on one character) strtoupper(''string'') PHP upper(''string'') Seed7 ${''string_param''^^} (mnemonic: ^ is pointing up) Bash [[echo (command)|echo]] "string" <nowiki>|</nowiki> [[tr (program)|tr]] 'a-z' 'A-Z'|Unix|-| translate(''string'') UPPER variables PARSE UPPER VAR SrcVar DstVar|Rexx|-| ''string''.upper|Python|-| upcase(''string'')|Pick Basic|-| ''string''.upcase|Ruby|-| strings.ToUpper(''string'')|Go|-| (string-upcase ''string'')|Scheme, Common Lisp|-| String.uppercase ''string''|OCaml|-| String.map Char.toUpper ''string''|Standard ML|-| map Char.toUpper ''string''|Haskell|-| ''string''.toUpperCase|Java, JavaScript|-| to_upper(''string'')|Erlang|-| ''string''.ToUpper|VB .NET, C#, Windows PowerShell, F#|-| ''string''.uppercaseString|Objective-C (NSString * only), Swift (Foundation)|-| string.upper(''string'') (''string''):upper|Lua|-| ''string'' asUppercase|Smalltalk|-| UPPER(''string'')|SQL|-| ToUpperCase[''string'']|Mathematica|-| «FUNCTION» UPPER-CASE(''string'')|COBOL|-| ''string''.toUpper|Cobra|-| string toupper ''string''| Tcl|-| ''string''.to_uppercase| Rust^[42] |} // Example in C#"Wiki means fast?".ToUpper; // "WIKI MEANS FAST?" Example in Perl 5 uc("Wiki means fast?"); # "WIKI MEANS FAST?" Example in Raku uc("Wiki means fast?"); # "WIKI MEANS FAST?""Wiki means fast?".uc; # "WIKI MEANS FAST?" /* Example in Rexx */translate("Wiki means fast?") /* "WIKI MEANS FAST?" */ /* Example #2 */A='This is an example.'UPPER A /* "THIS IS AN EXAMPLE." */ /* Example #3 */A='upper using Translate Function.'Translate UPPER VAR A Z /* Z="UPPER USING TRANSLATE FUNCTION." */ Example in Scheme(use-modules (srfi srfi-13))(string-upcase "Wiki means fast?") ; "WIKI MEANS FAST?" ' Example in Visual BasicUCase("Wiki means fast?") ' "WIKI MEANS FAST?" trim See main article: Trim (programming). trim or strip is used to remove whitespace from the beginning, end, or both beginning and end, of a string. Example usage Languages ''String''.Trim([''chars'']) C#, VB.NET, Windows PowerShell ''string''.strip; D (.trim ''string'') Clojure ''sequence'' [ predicate? ] trim Factor (string-trim '(#\Space #\Tab #\Newline) ''string'') Common Lisp (string-trim ''string'') Scheme ''string''.trim Java, JavaScript (1.8.1+, Firefox 3.5+), Rust^[43] Trim(''String'') Pascal,^[44] QBasic, Visual Basic, Delphi ''string''.strip Python strings.Trim(''string'', ''chars'') Go LTRIM(RTRIM(''String'')) Oracle SQL, T-SQL strip(''string'' [,''option'', ''char'']) REXX string:strip(''string'' [,''option'', ''char'']) Erlang ''string''.strip ''string''.lstrip ''string''.rstrip Ruby ''string''.trim Raku trim(''string'') PHP, Raku [''string'' stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] Objective-C using Cocoa ''string'' withBlanksTrimmed ''string'' withoutSpaces ''string'' withoutSeparators Smalltalk (Squeak, Pharo) Smalltalk strip(string) SAS string trim ''$string'' Tcl TRIM(''string'') TRIM(ADJUSTL(''string'')) Fortran TRIM(''string'') SQL TRIM(''string'') LTrim(''string'') RTrim(''String'') ColdFusion String.trim ''string'' OCaml 4+ Other languages In languages without a built-in trim function, it is usually simple to create a custom function which accomplishes the same task. APL APL can use regular expressions directly:Trim←'^ +| +$'⎕RAlternatively, a functional approach combining Boolean masks that filter away leading and trailing spaces:Trim←Or reverse and remove leading spaces, twice:Trim←∘⌽⍣2 AWK In AWK, one can use regular expressions to trim: ltrim(v) = gsub(/^[\t]+/, "", v) rtrim(v) = gsub(/[\t]+$/, "", v) trim(v) = ltrim(v); rtrim(v) or: function ltrim(s) function rtrim(s) function trim(s) C/C++ There is no standard trim function in C or C++. Most of the available string libraries^[45] for C contain code which implements trimming, or functions that significantly ease an efficient implementation. The function has also often been called EatWhitespace in some non-standard C libraries. In C, programmers often combine a ltrim and rtrim to implement trim: include include void rtrim(char *str) void ltrim(char *str) void trim(char *str) The open source C++ library Boost has several trim variants, including a standard one:^[46] include trimmed = boost::algorithm::trim_copy("string"); With boost's function named simply trim the input sequence is modified in-place, and returns no result. Another open source C++ library Qt, has several trim variants, including a standard one:^[47] include trimmed = s.trimmed; The Linux kernel also includes a strip function, strstrip, since 2.6.18-rc1, which trims the string "in place". Since 2.6.33-rc1, the kernel uses strim instead of strstrip to avoid false warnings.^[48] Haskell A trim algorithm in Haskell: import Data.Char (isSpace) trim :: String -> String trim = f . f where f = reverse . dropWhile isSpace may be interpreted as follows: f drops the preceding whitespace, and reverses the string. f is then again applied to its own output. Note that the type signature (the second line) is optional. J The trim algorithm in J is a functional description: trim =. #~ [: (+./\ *. +./\.) ' '&~: </syntaxhighlight> That is: filter (<code>#~</code>) for non-space characters (<code>' '&~:</code>) between leading (<code>+./\</code>) and (<code>*.</code>) trailing (<code>+./\.</code>) spaces. ====JavaScript==== There is a built-in trim function in JavaScript 1.8.1 (Firefox 3.5 and later), and the ECMAScript 5 standard. In earlier versions it can be added to the String object's prototype as follows: <syntaxhighlight lang="javascript"> String.prototype.trim = function { return this.replace(/^\s+/g, "").replace(/\s+$/g, ""); }; </syntaxhighlight> ====Perl==== Perl 5 has no built-in trim function. However, the functionality is commonly achieved using [[regular expression]]s. Example: $string =~ s/^\s+//; # remove leading whitespace$string =~ s/\s+$//; # remove trailing whitespace or: $string =~ s/^\s+|\s+$//g ; # remove both leading and trailing whitespace These examples modify the value of the original variable $string. Also available for Perl is StripLTSpace in String::Strip from CPAN. There are, however, two functions that are commonly used to strip whitespace from the end of strings, chomp and chop: [http://perldoc.perl.org/functions/chop.html chop] removes the last character from a string and returns it. [http://perldoc.perl.org/functions/chomp.html chomp] removes the trailing newline character(s) from a string if present. (What constitutes a newline is $INPUT_RECORD_SEPARATOR dependent). In Raku, the upcoming sister language of Perl, strings have a trim method. Example: $string = $string.trim; # remove leading and trailing whitespace$string .= trim; # same thing Tcl The Tcl string command has three relevant subcommands: trim, trimright and trimleft. For each of those commands, an additional argument may be specified: a string that represents a set of characters to remove—the default is whitespace (space, tab, newline, carriage return). Example of trimming vowels: set string onomatopoeiaset trimmed [string trim $string aeiou] ;# result is nomatopset r_trimmed [string trimright $string aeiou] ;# result is onomatopset l_trimmed [string trimleft $string aeiou] ;# result is nomatopoeia XSLT XSLT includes the function normalize-space(''string'') which strips leading and trailing whitespace, in addition to replacing any whitespace sequence (including line breaks) with a single space. Example: XSLT 2.0 includes regular expressions, providing another mechanism to perform string trimming. Another XSLT technique for trimming is to utilize the XPath 2.0 substring function. References

Notes and References

1. In Rust, the str::chars method iterates over code points and the std::iter::Iterator::nth method on iterators returns the zero-indexed nth value from the iterator, or None.
2. In C++, the overloaded operator<=> method on a string returns a std::strong_ordering object (otherwise std::weak_ordering): less, equal (same as equivalent), or greater.
3. returns LESS, EQUAL, or GREATER
4. returns LT, EQ, or GT
5. returns .TRUE. or .FALSE.. These functions are based on the ASCII collating sequence.
6. IBM extension.
7. In Rust, the Ord::cmp method on a string returns an Ordering: Less, Equal, or Greater.
8. In Rust, the operators == and != and the methods eq, ne are implemented by the PartialEq trait, and the operators <, >, <=, >= and the methods lt, gt, le, ge are implemented by the PartialOrd trait.
9. The operators use the compiler's default collating sequence.
10. modifies string<sub>1</sub>, which must have enough space to store the result
11. In Rust, the + operator is implemented by the Add trait.
12. See the str::contains method.
13. See the std::basic_string::contains method.
14. startpos is IBM extension.
15. See the str::find method.
16. startpos is IBM extension.
17. Web site: scan in Fortran Wiki . Fortranwiki.org . 2009-04-30 . 2013-08-18.
18. Web site: verify in Fortran Wiki . Fortranwiki.org . 2012-05-03 . 2013-08-18.
19. formatstring must be a fixed literal at compile time for it to have the correct type.
20. See std::format, which is imported by the Rust prelude so that it can be used under the name format.
21. See the slice::join method.
22. if n is larger than the length of the string, then in Debug mode ArrayRangeException is thrown, in Release mode, the behaviour is unspecified.
23. if n is larger than the length of the string, Java will throw an IndexOutOfBoundsException
24. if n is larger than length of string, raises Invalid_argument
25. if n is larger than length of string, throw the message "StringTake::take:"
26. In Rust, strings are indexed in terms of byte offsets and there is a runtime panic if the index is out of bounds or if it would result in invalid UTF-8. A &str (string reference) can be indexed by various types of ranges, including Range (0..n), RangeFrom (n..), and RangeTo (..n) because they all implement the SliceIndex trait with str being the type being indexed.

    The str::get method is the non-panicking way to index. It returns None in the cases in which indexing would panic.

27. Ruby lacks Unicode support
28. See the str::len method.
29. In Rust, the str::chars method iterates over code points and the std::iter::Iterator::count method on iterators consumes the iterator and returns the total number of elements in the iterator.
30. operates on one character
31. The transform function exists in the std:: namespace. You must include the <algorithm> header file to use it. The tolower and toupper functions are in the global namespace, obtained by the <ctype.h> header file. The std::tolower and std::toupper names are overloaded and cannot be passed to std::transform without a cast to resolve a function overloading ambiguity, e.g. std::transform(''string''.begin, ''string''.end, ''result''.begin, (int (*)(int))std::tolower);
32. [[std::string]] only, result is stored in string result which is at least as long as string, and may or may not be string itself
33. only ASCII characters as Ruby lacks Unicode support
34. See the str::to_lowercase method.
35. See the str::replace method.
36. In Rust, the str::chars method iterates over code points, the std::iter::Iterator::rev method on reversible iterators (std::iter::DoubleEndedIterator) creates a reversed iterator, and the std::iter::Iterator::collect method consumes the iterator and creates a collection (which here is specified as a String with the turbofish syntax) from the iterator's elements.
37. See the str::rfind method.
38. Web site: Annotated ES5 . Es5.github.com . 2013-08-18 . 2013-01-28 . https://web.archive.org/web/20130128185825/https://es5.github.com/#x15.5.4.13 . dead .
39. if n is larger than length of string, then in Debug mode ArrayRangeException is thrown, and unspecified behaviour in Release mode
40. See the str::split and str::rsplit methods.
41. [[std::string]] only, result is stored in string result which is at least as long as string, and may or may not be string itself
42. In Rust, the str::to_uppercase method returns a newly allocated String with any lowercase characters changed to uppercase ones following the Unicode rules.
43. In Rust, the str::trim method returns a reference to the original &str.
44. Web site: Trim – GNU Pascal priručnik . Gnu-pascal.de . 2013-08-24.
45. Web site: String library comparison . And.org . 2013-08-24.
46. Web site: Usage – 1.54.0 . Boost.org . 2013-05-22 . 2013-08-24.
47. http://doc.trolltech.com/4.5/qstring.html#trimmed
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