Stringfunctions are used in computerprogramming languages to manipulate astring or query information about a string (some do both).
Most programming languages that have a stringdatatype 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, likeC# andJava have immutable strings and return a copy (in newly allocated dynamic memory), while others, likeC manipulate the original string unless the programmer copies data to a new string. See for exampleConcatenation below.
The most basic example of a string function is thelength(string) function. This function returns the length of astring literal.
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 aslen(string). The below list of common functions aims to help limit this confusion.
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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, stringconcatenation andregular expressions are handled in separate pages. Statements inguillemets (« … ») are optional.[citation needed]
| Definition | charAt(string,integer) returns character. |
|---|---|
| Description | Returns character at index in the string. |
| Equivalent | Seesubstring 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,[1]PHP,Ruby,[1]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[2] | 0 |
string[i,1] | Pick Basic | 1 |
String.sub (string,i) | Standard ML | 0 |
string !!i | Haskell | 0 |
(string-refstringi) | Scheme | 0 |
(charstringi) | Common Lisp | 0 |
(eltstringi) | ISLISP | 0 |
(getstringi) | Clojure | 0 |
substr(string,i, 1) | Perl 5[1] | 0 |
substr(string,i, 1)string.substr(i, 1) | Raku[3] | 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] | 1 |
string at:i | Smalltalk (w/ bounds checking) | 1 |
string indexstring i | Tcl | 0 |
StringTake[string, {i}] | Mathematica,Wolfram Language[1] | 1 |
string@i | Eiffel | 1 |
string (i:1) | COBOL | 1 |
${string_param:i:1} | Bash | 0 |
i⌷string | APL | 0 or 1 |
{ Example in Pascal }varMyStr:string='Hello, World';MyChar:Char;beginMyChar:=MyStr[2];// 'e'
# Example in ALGOL 68 #"Hello, World"[2]; // 'e'
// Example in C#include<stdio.h>charmyStr1[]="Hello, World";printf("%c",*(myStr1+1));// 'e'printf("%c",*(myStr1+7));// 'W'printf("%c",myStr1[11]);// 'd'printf("%s",myStr1);// 'Hello, World'printf("%s","Hello(2), World(2)");// 'Hello(2), World(2)'
importstd;usingstd::string;charmyStr1[]="Hello(1), World(1)";stringmyStr2="Hello(2), World(2)";std::println("Hello(3), World(3)");// 'Hello(3), World(3)'std::println("{}",myStr2[6]);// '2'std::println("{}",myStr1.substr(5,3));// '(1)'
// Example in C#"Hello, World"[2];// 'l'
# Example in Perl 5substr("Hello, World",1,1);# 'e'
# Examples in Python"Hello, World"[2]# 'l'"Hello, World"[-3]# 'r'
# Example in Raku"Hello, World".substr(1,1);# 'e'
' Example in Visual BasicMid("Hello, World",2,1)
' Example in Visual Basic .NET"Hello, World".Chars(2)' "l"c
" Example in Smalltalk "'Hello, World'at:2."$e"
//Example in Rust"Hello, World".chars().nth(2);// Some('l')
| Definition | compare(string1,string2) 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 islexicographically 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 |
|---|---|
IFstring1<string2 THEN -1 ELSE ABS (string1>string2) FI | ALGOL 68 |
cmp(string1,string2) | Python 2 |
(string1 >string2) - (string1 <string2) | Python |
strcmp(string1,string2) | C,PHP |
std.string.cmp(string1,string2) | D |
StrComp(string1,string2) | VB,Object Pascal (Delphi) |
string1 cmpstring2 | Perl,Raku |
string1 compare:string2 | Smalltalk (Squeak,Pharo) |
string1 <=>string2 | Ruby,C++ (STL,C++20)[4] |
string1.compare(string2) | C++ (STL),Swift (Foundation) |
compare(string1,string2) | Rexx,Seed7 |
compare(string1,string2,pad) | Rexx |
CompareStr(string1,string2) | Pascal,Object Pascal (Delphi) |
string1.compareTo(string2) | Cobra,Java |
string1.CompareTo(string2) | VB .NET,C#,F# |
(comparestring1string2) | Clojure |
(string=string1string2) | Common Lisp |
(string-comparestring1string2p<p=p>) | Scheme (SRFI 13) |
(string=string1string2) | ISLISP |
comparestring1string2 | OCaml |
String.compare (string1,string2) | Standard ML[5] |
comparestring1string2 | Haskell[6] |
[string]::Compare(string1,string2) | Windows PowerShell |
[string1 compare:string2] | Objective-C (NSString * only) |
LLT(string1,string2)LLE(string1,string2)LGT(string1,string2)LGE(string1,string2) | Fortran[7] |
string1.localeCompare(string2) | JavaScript |
| Go |
string comparestring1string2 | Tcl |
compare(string1,string2,count) | PL/I[8] |
string1.cmp(string2) | Rust[9] |
# Example in Perl 5"hello"cmp"world";# returns -1
# Example in Pythoncmp("hello","world")# returns -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(srfisrfi-13)); returns index of mismatch: 0(string-compare"hello""world"valuesvaluesvalues)
| Definition | string1 OP string2 OR(compare string1 string2) returns Boolean. |
|---|---|
| Description | Lexicographically compares two strings using a relational operator or function. Boolean result returned. |
| Format | Languages |
|---|---|
string1 OPstring2, whereOP can be any of=, <>, <, >, <= and>= | Pascal,Object Pascal (Delphi),OCaml,Seed7,Standard ML,BASIC,VB,VB .NET,F# |
string1 OPstring2, whereOP can be any of=, /=, ≠, <, >, <=, ≤ and≥; Also:EQ, NE, LT, LE, GE andGT | ALGOL 68 |
(stringOP?string1string2), whereOP can be any of=, -ci=, <, -ci<, >, -ci>, <=, -ci<=, >= and-ci>= (operators starting with '-ci' are case-insensitive) | Scheme |
(stringOPstring1string2), whereOP can be any of=, -ci=, <>, -ci<>, <, -ci<, >, -ci>, <=, -ci<=, >= and-ci>= (operators starting with '-ci' are case-insensitive) | Scheme (SRFI 13) |
(stringOPstring1string2), whereOP can be any of=, -equal, /=, -not-equal, <, -lessp, >, -greaterp, <=, -not-greaterp, >= and-not-lessp (the verbal operators are case-insensitive) | Common Lisp |
(stringOPstring1string2), whereOP can be any of=, /=, <, >, <=, and>= | ISLISP |
string1 OPstring2, whereOP can be any of=, \=, <, >, <= and>=[10] | Rexx |
string1 OPstring2, whereOP can be any of=, ¬=, <, >, <=, >=, ¬< and¬>[11] | PL/I |
string1 OPstring2, whereOP can be any of=, /=, <, >, <= and>= | Ada |
string1 OPstring2, whereOP can be any of==, /=, <, >, =< and>= | Erlang |
string1 OPstring2, whereOP can be any of==, /=, <, >, <= and>= | Haskell |
string1 OPstring2, whereOP can be any ofeq,ne,lt,gt,le andge | Perl,Raku |
string1 OPstring2, whereOP can be any of==, !=, <, >, <= and>= | C++ (STL),C#,D,Go,JavaScript,Python,PHP,Ruby,Rust,[12]Swift |
string1 OPstring2, whereOP 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 |
string1 OPstring2, whereOP can be any of==, ~=, <, >, <= and>= | Lua |
string1 OPstring2, whereOP can be any of=, ~=, <, >, <= and>= | Smalltalk |
string1 OPstring2, whereOP can be any of==, /=, <, >, <= and>=; Also: .EQ., .NE., .LT., .LE., .GT. and.GE. | Fortran.[13] |
string1 OPstring2 whereOP can be any of=, <>, <, >, <=, >= as well as worded equivalents | COBOL |
string1 OPstring2 whereOP can be any of==, <>, <, >, <= and>= | Cobra |
string1 OPstring2 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 |
string1.METHOD(string2) whereMETHOD is any ofeq,ne,gt,lt,ge,le | Rust[12] |
% Example in Erlang"hello">"world".% returns false
# Example in Raku"art"gt"painting";# returns False"art"lt"painting";# returns True
# Example in Windows PowerShell"hello"-gt"world"# returns false
;; Example in Common Lisp(string>"art""painting"); returns nil(string<"art""painting"); returns non nil
| Definition | concatenate(string1,string2) 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 |
|---|---|
string1adjacent_tostring2 | Rexx (abutment, equivalent tostring1 ||string2) |
string1whitespacestring2 | Rexx (equivalent tostring1 || ' ' ||string2) |
string1 &string2 | Ada,FreeBASIC,Seed7,BASIC,VB,VB .NET,COBOL (between literals only) |
strcat(string1,string2) | C,C++ (char* only)[14] |
string1 .string2 | Perl,PHP |
string1 +string2 | ALGOL 68,C++ (STL),C#,Cobra,FreeBASIC,Go,Pascal,Object Pascal (Delphi),Java,JavaScript,Windows PowerShell,Python,Ruby,Rust,[15]F#,Swift,Turing,VB |
string1 ~string2 | D,Raku |
(string-appendstring1string2) | Scheme,ISLISP |
(concatenate 'stringstring1string2) | Common Lisp |
(strstring1string2) | Clojure |
string1 ||string2 | Rexx,SQL,PL/I |
string1 //string2 | Fortran |
string1 ++string2 | Erlang,Haskell |
string1 ^string2 | OCaml,Standard ML,F# |
[string1 stringByAppendingString:string2] | Objective-C (NSString * only) |
string1 ..string2 | Lua |
string1 ,string2 | Smalltalk,APL |
string1string2 | SNOBOL |
string1string2 | Bash |
string1 <>string2 | Mathematica |
| concatstring1 string2 | Tcl |
{ Example in Pascal }'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"
# Example in Perl 5"abc"."def";# returns "abcdef""Perl ".5;# returns "Perl 5"
/* Example in PL/I */"abc"||"def"/* returns "abcdef" */
# Example in Raku"abc" ~"def";# returns "abcdef""Perl " ~6;# returns "Perl 6"
/* Example in Rexx */"Strike"2/* returns "Strike2" */"Strike"2/* returns "Strike 2" */
| Definition | contains(string,substring) returns boolean |
|---|---|
| Description | Returns whetherstring containssubstring as a substring. This is equivalent to usingFind 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,[16]C++ (C++23)[17] |
string.indexOf(substring) >= 0 | JavaScript |
strpos(string,substring) !== false | PHP |
str_contains(string,substring) | PHP (8+) |
pos(string,substring) <> 0 | Seed7 |
substring instring | Cobra,Python (2.3+) |
string.find(string,substring) ~= nil | Lua |
string.include?(substring) | Ruby |
Data.List.isInfixOfsubstringstring | Haskell (GHC 6.6+) |
string includesSubstring:substring | Smalltalk (Squeak,Pharo,Smalltalk/X) |
String.isSubstringsubstringstring | Standard ML |
(searchsubstringstring) | Common Lisp |
| ISLISP |
(substring?substringstring) | Clojure |
! StringFreeQ[string,substring] | Mathematica |
index(string,substring,startpos)>0 | Fortran, PL/I[18] |
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 inALGOL 68 ¢string in string("e",loc int, "Hello mate"); ¢ returnstrue ¢string in string("z",loc int, "word"); ¢ returnsfalse ¢
// Example In C#"Hello mate".Contains("e");// returns true"word".Contains("z");// returns false
# Example in Python"e"in"Hello mate"# returns true"z"in"word"# returns false
# 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 "
Tests if two strings are equal. See also#Compare and#Compare. Note that doing equality checks via a genericCompare 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 |
|---|---|
string1 ==string2 | Python,C++ (STL),C#,Cobra,Go,JavaScript (similarity),PHP (similarity),Ruby,Rust,[12]Erlang,Haskell,Lua,D,Mathematica,Swift |
string1 ===string2 | JavaScript,PHP |
string1 ==string2string1 .EQ.string2 | Fortran |
strcmp(string1,string2) == 0 | C |
(string=?string1string2) | Scheme |
(string=string1string2) | Common Lisp,ISLISP |
string1 =string2 | ALGOL 68,Ada,Object Pascal (Delphi),OCaml,Pascal,Rexx,Seed7,Standard ML,BASIC,VB,VB .NET,F#,Smalltalk,PL/I,COBOL |
teststring1 =string2[string1 =string2 ] | Bourne Shell |
string1 eqstring2 | Perl,Raku,Tcl |
string1.equals(string2) | Cobra,Java |
string1.Equals(string2) | C# |
string1 -eqstring2[string]::Equals(string1,string2) | Windows PowerShell |
[string1 isEqualToString:string2][string1 isEqual:string2] | Objective-C (NSString * only) |
string1 ≡string2 | APL |
string1.eq(string2) | Rust[12] |
// Example in C#"hello"=="world"// returns false
' Example in Visual Basic"hello"="world"' returns false
# Examples in Perl 5'hello'eq'world'# returns 0'hello'eq'hello'# returns 1
# Examples in Raku'hello'eq'world'# returns False'hello'eq'hello'# returns True
# Example in Windows PowerShell"hello"-eq"world"# returns false
⍝ Example in APL'hello'≡'world'⍝ returns 0
| Definition | find(string,substring) returns integer |
|---|---|
| Description | Returns the position of the start of the first occurrence ofsubstring instring. If thesubstring 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++ (char* 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-containsstringsubstring) | Scheme (SRFI 13) | returns #f |
(searchsubstringstring) | Common Lisp | returns NIL |
(string-indexsubstringstring) | ISLISP | returnsnil |
List.findIndex (List.isPrefixOfsubstring) (List.tailsstring) | Haskell (returns onlyindex) | returns Nothing |
Str.search_forward (Str.regexp_stringsubstring)string 0 | OCaml | raises Not_found |
Substring.size (#1 (Substring.positionsubstring (Substring.fullstring))) | 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:aBlockstring 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 INstring) | SQL | returns 0 (positions start at 1) |
index(string,substring,startpos ) | PL/I[18] | 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 firstsubstring string startpos | Tcl | returns −1 |
(substring⍷string)⍳1 | APL | returns 1 + the last position instring |
string.find(substring) | Rust[19] | returnsNone |
Examples
(search"e""Hello mate"); returns 1(search"z""word"); returns NIL
"Hello mate".IndexOf("e");// returns 1"Hello mate".IndexOf("e",4);// returns 9"word".IndexOf("z");// returns -1
"Hello, there!".index('e')# returns 1"Hello, there!".index('z')# returns Nil
(use-modules(srfisrfi-13))(string-contains"Hello mate""e"); returns 1(string-contains"word""z"); returns #f
' Examples inInStr("Hello mate","e")' returns 2InStr(5,"Hello mate","e")' returns 10InStr("word","z")' returns 0
'Hello mate'indexOfSubCollection:'ate'"returns 8"
'Hello mate'indexOfSubCollection:'late'"returns 0"
I'Hellomate'indexOfSubCollection:'late'ifAbsent:[99 ]"returns 99"
'Hello mate'indexOfSubCollection:'late'ifAbsent:[selferror ]"raises an exception"
| Definition | find_character(string,char) returns integer |
|---|---|
| Description | Returns the position of the start of the first occurrence of the characterchar instring. 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 | returnsBOOL:TRUE orFALSE, and position inREF INT pos. |
instr(string, anychar«,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++ (char* only, returns pointer to character) | returnsNULL |
std.string.find(string,dchar) | D | returns −1 |
string.find(char«,startpos») | C++ (STL) | returnsstd::string::npos |
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 |
(positioncharstring) | Common Lisp | returnsNIL |
(char-indexcharstring) | ISLISP | returnsnil |
List.elemIndexcharstring | Haskell (returnsJustindex) | returnsNothing |
String.indexstringchar | OCaml | raisesNot_found |
position = SCAN (string,set «,back» «,kind»)position = VERIFY (string,set «,back» «,kind»)[a] | Fortran | returns zero |
string indexOf:char ifAbsent: aBlockstring indexOf:charstring includes:char | Smalltalk | evaluateaBlock which is aBlockClosure (or any object understanding value)returns 0 returns true orfalse |
index(string,char,startpos ) | PL/I[20] | returns 0 (positions start at 1) |
string.index(?char) | Ruby | returnsnil |
strpos(string,char,startpos) | PHP | returnsfalse |
string.indexOf(char«,startpos«,charcount»») | Cobra | returns −1 |
string⍳char | APL | returns 1 + the last position instring |
string.find(substring) | Rust[19] | returnsNone |
// 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
^a Given a set of characters, SCAN returns the position of the first character found,[21] while VERIFY returns the position of the first character that does not belong to the set.[22]
| 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 |
printfformatstringitems | Unix | C |
formatstring % (items) | Python,Ruby | C |
formatstring.format(items) | Python | .NET |
fformatstring | Python 3 | |
Printf.sprintfformatstring[23]items | OCaml,F# | C |
Text.Printf.printfformatstringitems | Haskell (GHC) | C |
formatstring printf:items | Smalltalk | C |
String.format(formatstring,items) | Java | C |
String.Format(formatstring,items) | VB .NET,C#,F# | .NET |
(formatformatstringitems) | Scheme (SRFI 28) | Lisp |
(format nilformatstringitems) | Common Lisp | Lisp |
(formatformatstringitems) | Clojure | Lisp |
formatstring -fitems | 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 |
formatformatstring items | Tcl | C |
formatnumbers ⍕itemsformatstring ⎕FMTitems | APL | APL |
format!(formatstring,items) | Rust[24] | Python |
// Example in C#String.Format("My {0} costs {1:C2}","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"
# Examples in Rakusprintf"My %s costs \$%.2f","pen",19.99;# returns "My pen costs $19.99"1.fmt("%04d");# returns "0001"
# Example in Python"My%s costs $%.2f"%("pen",19.99);# returns "My pen costs $19.99""My{0} costs ${1:.2f}".format("pen",19.99);# returns "My pen costs $19.99"
#Example in Python 3.6+pen="pen"f"My{pen} costs{19.99}"#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 */putstring(some_string)edit('My ','pen',' costs',19.99)(a,a,a,p'$$$V.99')/* returns "My pen costs $19.99" */
Tests if two strings are not equal. See also#Equality.
| Format | Languages |
|---|---|
string1nestring2string1 NEstring2 | ALGOL 68 – note: the operator "ne" is literally inbold type-font. |
string1 /=string2 | ALGOL 68,Ada,Erlang,Fortran,Haskell |
string1 <>string2 | BASIC,VB,VB .NET,Pascal,Object Pascal (Delphi),OCaml,PHP,Seed7,Standard ML,F#,COBOL,Cobra,Python 2 (deprecated) |
string1 #string2 | BASIC (some implementations) |
string1 nestring2 | Perl,Raku |
(string<>string1string2) | Scheme (SRFI 13) |
(string/=string1string2) | Common Lisp |
(string/=string1string2) | ISLISP |
(not=string1string2) | Clojure |
string1 !=string2 | C++ (STL),C#,Go,JavaScript (not similar),PHP (not similar),Python,Ruby,Rust,[12]Swift,D,Mathematica |
string1 !==string2 | JavaScript,PHP |
string1 \=string2 | Rexx |
string1 ¬=string2 | PL/I |
teststring1 !=string2[string1 !=string2 ] | Bourne Shell |
string1 -nestring2 | Windows PowerShell |
string1 ~=string2 | Lua,Smalltalk |
string1 ≢string2 | APL |
string1.ne(string2) | Rust[12] |
// Example in C#"hello"!="world"// returns true
' Example in Visual Basic"hello"<>"world"' returns true
;; Example in Clojure(not="hello""world"); ⇒ true
# Example in Perl 5'hello'ne'world'# returns 1
# Example in Raku'hello'ne'world'# returns True
# Example in Windows PowerShell"hello"-ne"world"# returns true
see#Find
see#Find
see#Find
see#rfind
| 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 ofsplit. |
| 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[25] |
(string-joinarray_of_stringsseparator) | Scheme (SRFI 13) |
(format nil "~{~a~^separator~}"array_of_strings) | Common Lisp |
(clojure.string/joinseparatorlist_of_strings)(apply str (interposeseparatorlist_of_strings)) | Clojure |
strings.Join(array_of_strings,separator) | Go |
join(array_of_strings,separator) | Seed7 |
String.concatseparatorlist_of_strings | OCaml |
String.concatWithseparatorlist_of_strings | Standard ML |
Data.List.intercalateseparatorlist_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 -joinseparator | Windows PowerShell |
[array_of_strings componentsJoinedByString:separator] | Objective-C (NSString * only) |
table.concat(table_of_strings,separator) | Lua |
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"})// "a-b-c"
" Example in Smalltalk "#('a''b''c')joinUsing:'-'" 'a-b-c' "
# Example in Perl 5join('-',('a','b','c'));# 'a-b-c'
# Example in Raku<a b c>.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(srfisrfi-13))(string-join'("a""b""c")"-"); "a-b-c"
see#rfind
| Definition | left(string,n) returns string |
|---|---|
| Description | Returns the leftn part of a string. Ifn 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 asUTF-8,UTF-16 orShift-JIS, it can be necessary to remove string positions at the end, in order to avoid invalid strings. |
| Format | Languages |
|---|---|
| Ada |
substr(string, 0,n) | AWK (changes string),Perl,PHP,Raku |
LEFT$(string,n) | BASIC,VB |
left(string,n) | VB,FreeBASIC,Ingres,Pick Basic |
strncpy(string2,string,n) | C standard library |
string.substr(0,n) | C++ (STL),Raku |
[string substringToIndex:n] | Objective-C (NSString * only) |
| Clojure |
string[0 ..n] | D[26] |
string:substr(string,start,length) | Erlang |
(subseqstring 0n) | Common Lisp |
string[:n] | Cobra,Go,Python |
left(string,n «,padchar») | Rexx,Erlang |
string[0,n]string[0..n - 1] | Ruby |
string[1,n] | Pick Basic |
string[ ..n] | Seed7 |
string.Substring(0,n) | VB .NET,C#,Windows PowerShell,F# |
leftstr(string,n) | Pascal,Object Pascal (Delphi) |
copy (string,1,n) | Turbo Pascal |
string.substring(0,n) | Java,[27]JavaScript |
(string-takestringn) | Scheme (SRFI 13) |
takenstring | Haskell |
String.extract (string,n, NONE) | Standard ML |
String.substring 0n | OCaml[28] |
string.[..n] | F# |
string.sub(string, 1,n)(string):sub(1,n) | Lua |
string first:n | Smalltalk (Squeak,Pharo) |
string(:n) | Fortran |
StringTake[string,n] | Mathematica[29] |
string («FUNCTION» LENGTH(string) -n:n) | COBOL |
string.substring(0,n) | Cobra |
n↑string. | APL |
string[0..n]string[..n]string.get(0..n)string.get(..n) | Rust[30] |
# Example in Raku"Hello, there!".substr(0,6);# returns "Hello,"
/* Examples in Rexx */left("abcde",3)/* returns "abc" */left("abcde",8)/* returns "abcde " */left("abcde",8,"*")/* returns "abcde***" */
; Examples in Scheme(use-modules(srfisrfi-13))(string-take"abcde",3); returns "abc"(string-take"abcde",8); error
' Examples in Visual BasicLeft("sandroguidi",3)' returns "san"Left("sandroguidi",100)' returns "sandroguidi"
see#length
| Definition | length(string) returns an integer number |
|---|---|
| Description | Returns the length of a string (not counting thenull terminator or any other of the string's internal structural information). An empty string returns a length of 0. |
| Format | Returns | Languages |
|---|---|---|
string'Length | | Ada |
UPB string | | ALGOL 68 |
echo "${#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 ofUTF-16code 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 ORstring.length | Number of bytes[31] | Ruby |
strlen(string) | Number of bytes | C,PHP |
string.length() | | C++ (STL) |
string.length | | Cobra,D,JavaScript |
string.length() | Number ofUTF-16code units | Java |
(string-lengthstring) | | Scheme |
(lengthstring) | | Common Lisp,ISLISP |
(countstring) | | Clojure |
String.lengthstring | | OCaml |
sizestring | | Standard ML |
lengthstring | Number of Unicode code points | Haskell |
string.length | Number ofUTF-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
| number of characters and number of bytes, respectively | COBOL |
string lengthstring | a decimal string giving the number of characters | Tcl |
≢string | APL | |
string.len() | Number of bytes | Rust[32] |
string.chars().count() | Number of Unicode code points | Rust[33] |
// Examples in C#"hello".Length;// returns 5"".Length;// returns 0
#ExamplesinErlangstring:len("hello").% returns 5string:len("").% returns 0
# Examples in Perl 5length("hello");# returns 5length("");# returns 0
# Examples in Raku"".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
see#Find
| 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[34] |
std.string.toLower(string) | D |
transform(string.begin(),string.end(),result.begin(), ::tolower)[35] | C++[36] |
lowercase(string) | Object Pascal (Delphi) |
strtolower(string) | PHP |
lower(string) | Seed7 |
${string_param,,} | Bash |
echo "string" |tr 'A-Z' 'a-z' | Unix |
string.lower() | Python |
downcase(string) | Pick Basic |
string.downcase | Ruby[37] |
strings.ToLower(string) | Go |
(string-downcasestring) | Scheme (R6RS),Common Lisp |
(lower-casestring) | Clojure |
String.lowercasestring | OCaml |
String.map Char.toLowerstring | Standard ML |
map Char.toLowerstring | 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[8] |
ToLowerCase[string] | Mathematica |
«FUNCTION» LOWER-CASE(string) | COBOL |
string.toLower | Cobra |
string tolowerstring | Tcl |
string.to_lowercase() | Rust[38] |
// Example in C#"Wiki means fast?".ToLower();// "wiki means fast?"
; Example in Scheme(use-modules(srfisrfi-13))(string-downcase"Wiki means fast?"); "wiki means fast?"
/* Example in C */#include<ctype.h>#include<stdio.h>intmain(void){chars[]="Wiki means fast?";for(inti=0;i<sizeof(s)-1;++i){// transform characters in place, one by ones[i]=tolower(s[i]);}printf(string);// "wiki means fast?"return0;}
# Example in Raku"Wiki means fast?".lc;# "wiki means fast?"
see#substring
| Definition | <string>.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 | |
splitseparator,string, 2string.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 / Rakusplit/(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');
| Definition | replace(string,find,replace) returns string |
|---|---|
| Description | Returns a string withfind occurrences changed toreplace. |
| 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[39] |
string.replaceAll(find_regex,replace)[40] | Java |
string.gsub(find,replace) | Ruby |
string =~ s/find_regex/replace/g[40] | Perl 5 |
string.subst(find,replace, :g) | Raku |
string.replace(find,replace, "g")[41]string.replace(/find_regex/g,replace)[40] | JavaScript |
echo "string" |sed 's/find_regex/replace/g'[40] | Unix |
${string_param//find_pattern/replace} | Bash |
string.replace(find,replace)string -replacefind_regex,replace[40] | Windows PowerShell |
Str.global_replace (Str.regexp_stringfind)replacestring | 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 {findreplace}string | Tcl |
StringReplace[string,find ->replace] | Mathematica |
strings.Replace(string,find,replace, -1) | Go |
INSPECTstring REPLACING ALL/LEADING/FIRSTfind BYreplace | COBOL |
find_regex ⎕Rreplace_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"
//ExamplesinRaku"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"
| Definition | reverse(string) |
|---|---|
| Description | Reverses the order of the characters in the string. |
| Format | Languages |
|---|---|
reversestring | Perl 5,Haskell |
flipstringstring.flip | Raku |
lists:reverse(string) | Erlang |
strrev(string) | PHP |
string[::-1] | Python |
(string-reversestring) | Scheme (SRFI 13) |
(reversestring) | 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 (explodestring)) | Standard ML |
string | JavaScript |
string.reverse(string)(string):reverse() | Lua |
string reverse | Smalltalk |
StringReverse[string] | Mathematica |
reverse(string) | PL/I |
| COBOL |
string.toCharArray.toList.reversed.join() | Cobra |
String(string.characters.reverse()) | Swift (2.x) |
String(reverse(string)) | Swift (1.2) |
string reversestring | Tcl |
⌽string | APL |
string | Rust[42] |
echostring | rev | Unix |
" Example in Smalltalk "'hello'reversed" returns 'olleh' "
# Example in Perl 5reverse"hello"# returns "olleh"
# Example in Raku"hello".flip# returns "olleh"
# Example in Python"hello"[::-1]# returns "olleh"
; Example in Scheme(use-modules(srfisrfi-13))(string-reverse"hello"); returns "olleh"
| Definition | rfind(string,substring) returns integer |
|---|---|
| Description | Returns the position of the start of the last occurrence ofsubstring instring. If thesubstring 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 | returnsNil |
strrpos(string,substring«,startpos») | PHP | returnsFALSE |
string.rfind(substring«,startpos») | C++ (STL) | returnsstd::string::npos |
std.string.rfind(string,substring) | D | returns −1 |
string.rfind(substring«,startpos«,endpos»») | Python | returns −1 |
string.rindex(substring«,startpos«,endpos»») | raisesValueError | |
rpos(string,substring«,startpos») | Seed7 | returns 0 |
string.rindex(substring«,startpos») | Ruby | returnsnil |
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 |
(searchsubstringstring :from-end t) | Common Lisp | returnsNIL |
[string rangeOfString:substring options:NSBackwardsSearch].location | Objective-C (NSString * only) | returnsNSNotFound |
Str.search_backward (Str.regexp_stringsubstring)string (Str.lengthstring - 1) | OCaml | raisesNot_found |
string.match(string, '.*()'..substring)string | Lua | returnsnil |
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 lastsubstring string startpos | Tcl | returns −1 |
| APL | returns −1 |
string.rfind(substring) | Rust[43] | returnsNone |
; Examples in Common Lisp(search"e""Hello mate":from-endt); returns 9(search"z""word":from-endt); 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 5rindex("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
| Definition | right(string,n) returns string |
|---|---|
| Description | Returns the rightn part of a string. Ifn is greater than the length of the string then most implementations return the whole string (exceptions exist – see code examples). |
| Format | Languages |
|---|---|
| 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 ofstring) | C |
string.Substring(string.Length()-n) | C# |
string[len(string)-n:] | Go |
string.substring(string.length()-n) | Java |
string.slice(-n) | JavaScript[44] |
right(string,n «,padchar») | Rexx,Erlang |
substr(string,-n) | Perl 5,PHP |
substr(string,*-n)string.substr(*-n) | Raku |
string[-n:] | Cobra,Python |
${string_param: -n} (note the space after the colon) | Bash |
string[n] | Pick Basic |
(string-take-rightstringn) | Scheme (SRFI 13) |
string[-n..-1] | Ruby |
string[$-n .. $] | D[45] |
String.substring (String.lengthstring -n)n | OCaml[28] |
string.sub(string, -n)(string):sub(-n) | Lua |
string last:n | Smalltalk (Squeak,Pharo) |
StringTake[string, -n] | Mathematica[29] |
string (1:n) | COBOL |
¯n↑string. | APL |
string[n..]string.get(n..) | Rust[30] |
// Examples in Java; extract rightmost 4 charactersStringstr="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(srfisrfi-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"
| Definition | <string>.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. |
| Format | Languages |
|---|---|
string.rpartition(separator) | Python,Ruby |
# 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')
see#substring
| Definition | <string>.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. Iflimit is given, afterlimit – 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 ofjoin. |
| 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-tokenizestring« charset« start« end»»») | Scheme (SRFI 13) |
Split(string,sepchars«,limit») | VB |
string.Split(sepchars«,limit«,options»») | VB .NET,C#,F# |
string -splitseparator«,limit«,options»» | Windows PowerShell |
Str.split (Str.regexp_stringseparator)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 |
splitstring separator | Tcl |
(separator≠string)⊂string in APL2separator(≠⊆⊢)string in Dyalog APL 16.0 | APL |
string.split(separator)
| Rust[46] |
// Example in C#"abc,defgh,ijk".Split(',');// {"abc", "defgh", "ijk"}"abc,defgh;ijk".Split(',',';');// {"abc", "defgh", "ijk"}
% Example in Erlangstring:tokens("abc;defgh;ijk",";").% ["abc", "defgh", "ijk"]
// Examples in Java"abc,defgh,ijk".split(",");// {"abc", "defgh", "ijk"}"abc,defgh;ijk".split(",|;");// {"abc", "defgh", "ijk"}
{ Example in Pascal }varlStrings:TStringList;lStr:string;beginlStrings:=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 5split(/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)
see#Format
see#trim
| Definition | substring(string,startpos,endpos) returns stringsubstr(string,startpos,numChars) returns string |
|---|---|
| Description | Returns a substring ofstring between starting atstartpos andendpos, or starting atstartpos of lengthnumChars. The resulting string is truncated if there are fewer thannumChars characters beyond the starting point.endpos represents the index after the last character in the substring. Note that for variable-length encodings such asUTF-8,UTF-16 orShift-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,[47][48]PHP[47][48] |
substr(string,startpos,numChars)string.substr(startpos,numChars) | Raku[49][50] |
substr(string,startpos «,numChars,padChar») | Rexx |
string[startpos:endpos] | Cobra,Python,[47][51]Go |
string[startpos,numChars] | Pick Basic |
string[startpos,numChars]string[startpos ..endpos-1]string[startpos ...endpos] | Ruby[47][51] |
string[startpos ..endpos]string[startpos lennumChars] | Seed7 |
string.slice(startpos«,endpos») | JavaScript[47][51] |
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) |
(substringstringstartposendpos) | Scheme |
(subseqstringstartposendpos) | Common Lisp |
(subseqstringstartposendpos) | ISLISP |
String.substringstartposnumChars | 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 |
takenumChars $ dropstartposstring | Haskell |
[string substringWithRange:NSMakeRange(startpos,numChars)] | Objective-C (NSString * only) |
string.[startpos..endpos] | F# |
string.sub(string,startpos,endpos)(string):sub(startpos,endpos) | Lua[47][51] |
string copyFrom:startpos to:endpos | Smalltalk |
string(startpos:endpos) | Fortran |
SUBSTRING(string FROMstartpos «FORnumChars») | SQL |
StringTake[string, {startpos,endpos}] | Mathematica[47][51] |
string (startpos:numChars) | COBOL |
${string_param:startpos:numChars} | Bash |
string rangestring startpos endpos | Tcl |
string[startpos..endpos]string.get(startpos..endpos) | Rust[30] |
// 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"12); 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 5substr("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****" */
| 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) |
| C (string / char array) |
std.string.toUpper(string) | D |
transform(string.begin(),string.end(),result.begin(), toupper)[35] | C++[52] |
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 "string" |tr 'a-z' 'A-Z' | Unix |
translate(string)UPPER variablesPARSEUPPERVARSrcVarDstVar | Rexx |
string.upper() | Python |
upcase(string) | Pick Basic |
string.upcase | Ruby[37] |
strings.ToUpper(string) | Go |
(string-upcasestring) | Scheme,Common Lisp |
String.uppercasestring | OCaml |
String.map Char.toUpperstring | Standard ML |
map Char.toUpperstring | Haskell |
string.toUpperCase() | Java,JavaScript |
string.uppercase() | Kotlin[53] |
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 |
| COBOL |
string.toUpper | Cobra |
string toupperstring | Tcl |
string.to_uppercase() | Rust[54] |
// Example in C#"Wiki means fast?".ToUpper();// "WIKI MEANS FAST?"
# Example in Perl 5uc("Wiki means fast?");# "WIKI MEANS FAST?"
# Example in Rakuuc("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.'UPPERA/* "THIS IS AN EXAMPLE." *//* Example #3 */A='upper using Translate Function.'TranslateUPPERVARAZ/* Z="UPPER USING TRANSLATE FUNCTION." */
; Example in Scheme(use-modules(srfisrfi-13))(string-upcase"Wiki means fast?"); "WIKI MEANS FAST?"
' Example in Visual BasicUCase("Wiki means fast?")' "WIKI MEANS FAST?"
trim orstrip 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 |
(.trimstring) | Clojure |
sequence [ predicate? ] trim | Factor |
| Common Lisp |
(string-trimstring) | Scheme |
string.trim() | Java,JavaScript (1.8.1+, Firefox 3.5+),Rust[55] |
Trim(String) | Pascal,[56]QBasic,Visual Basic,Delphi |
string.strip() | Python |
strings.Trim(string,chars) | Go |
LTRIM(RTRIM(String)) | OracleSQL,T-SQL |
strip(string [,option,char]) | REXX |
string:strip(string [,option,char]) | Erlang |
string.stripstring.lstripstring.rstrip | Ruby |
string.trim | Raku |
trim(string) | PHP,Raku |
[string | Objective-C usingCocoa |
string withBlanksTrimmedstring withoutSpacesstring 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.trimstring | 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 can use regular expressions directly:
Trim←'^ +| +$'⎕R''
Alternatively, a functional approach combining Boolean masks that filter away leading and trailing spaces:
Trim←{⍵/⍨(∨\∧∘⌽∨\∘⌽)' '≠⍵}
Or reverse and remove leading spaces, twice:
Trim←{(∨\' '≠⍵)/⍵}∘⌽⍣2
InAWK, one can use regular expressions to trim:
ltrim(v)=gsub(/^[ \t]+/,"",v)rtrim(v)=gsub(/[ \t]+$/,"",v)trim(v)=ltrim(v);rtrim(v)
or:
functionltrim(s){sub(/^[ \t]+/,"",s);returns}functionrtrim(s){sub(/[ \t]+$/,"",s);returns}functiontrim(s){returnrtrim(ltrim(s));}
There is no standard trim function in C or C++. Most of the available string libraries[57] for C contain code which implements trimming, or functions that significantly ease an efficient implementation. The function has also often been calledEatWhitespace in some non-standard C libraries.
In C, programmers often combine a ltrim and rtrim to implement trim:
#include<ctype.h>#include<string.h>voidrtrim(char*str){char*s;s=str+strlen(str);while(--s>=str){if(!isspace(*s)){break;}*s=0;}}voidltrim(char*str){size_tn;n=0;while(str[n]&&isspace((unsignedchar)str[n])){n++;}memmove(str,str+n,strlen(str)-n+1);}voidtrim(char*str){rtrim(str);ltrim(str);}
Theopen source C++ libraryBoost has several trim variants, including a standard one:[58]
#include<boost/algorithm/string/trim.hpp>trimmed=boost::algorithm::trim_copy("string");
With boost's function named simplytrim the input sequence is modified in-place, and returns no result.
Anotheropen source C++ libraryQt, has several trim variants, including a standard one:[59]
#include<QString>trimmed=s.trimmed();
TheLinux 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 usesstrim() instead ofstrstrip() to avoid false warnings.[60]
A trim algorithm inHaskell:
importData.Char(isSpace)trim::String->Stringtrim=f.fwheref=reverse.dropWhileisSpace
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.
The trim algorithm inJ is afunctional description:
trim=.#~[:(+./\*.+./\.)' '&~:
That is: filter (#~) for non-space characters (' '&~:) between leading (+./\) and (*.) trailing (+./\.) spaces.
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:
String.prototype.trim=function(){returnthis.replace(/^\s+/g,"").replace(/\s+$/g,"");};
Perl 5 has no built-in trim function. However, the functionality is commonly achieved usingregular expressions.
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$string.
Also available for Perl isStripLTSpace inString::Strip fromCPAN.
There are, however, two functions that are commonly used to strip whitespace from the end of strings,chomp andchop:
chop removes the last character from a string and returns it.chomp removes the trailing newline character(s) from a string if present. (What constitutes a newline is$INPUT_RECORD_SEPARATOR dependent).InRaku, the upcoming sister language of Perl, strings have atrim method.
Example:
$string =$string.trim;# remove leading and trailing whitespace$string .=trim;# same thing
TheTclstring command has three relevant subcommands:trim,trimright andtrimleft. For each of those commands, an additional argument may be specified: a string that represents a set of characters to remove—the default is whitespace (space, tab, newline, carriage return).
Example of trimming vowels:
setstringonomatopoeiasettrimmed[stringtrim$stringaeiou];# result is nomatopsetr_trimmed[stringtrimright$stringaeiou];# result is onomatopsetl_trimmed[stringtrimleft$stringaeiou];# result is nomatopoeia
XSLT includes the functionnormalize-space(string) which strips leading and trailing whitespace, in addition to replacing any whitespace sequence (including line breaks) with a single space.
Example:
<xsl:variablename='trimmed'><xsl:value-ofselect='normalize-space(string)'/></xsl:variable>
XSLT 2.0 includes regular expressions, providing another mechanism to perform string trimming.
Another XSLT technique for trimming is to utilize the XPath 2.0substring() function.
str::chars method iterates over code points and thestd::iter::Iterator::nth method on iterators returns the zero-indexed nth value from the iterator, orNone.operator<=> method on astring returns astd::strong_ordering object (otherwisestd::weak_ordering):less,equal (same asequivalent), orgreater..TRUE. or.FALSE.. These functions are based on the ASCII collating sequence.Ord::cmp method on astring returns anOrdering:Less,Equal, orGreater.eq,ne are implemented by thePartialEq trait, and the operators<,>,<=,>= and the methodslt,gt,le,ge are implemented by thePartialOrd trait.string1, which must have enough space to store the result+ operator is implemented by theAdd trait.str::contains method.std::basic_string::contains method.str::find method.startpos is IBM extension.formatstring must be a fixed literal at compile time for it to have the correct type.std::format, which is imported by the Rustprelude so that it can be used under the nameformat.slice::join method.&str (string reference) can beindexed by various types of ranges, includingRange (0..n),RangeFrom (n..), andRangeTo (..n) because they all implement theSliceIndex trait withstr being the type being indexed.Thestr::get method is the non-panicking way to index. It returnsNone in the cases in which indexing would panic.str::len method.str::chars method iterates over code points and thestd::iter::Iterator::count method on iterators consumes the iterator and returns the total number of elements in the iterator.transform function exists in thestd:: namespace. You must include the<algorithm> header file to use it. Thetolower andtoupper functions are in the global namespace, obtained by the<ctype.h> header file. Thestd::tolower andstd::toupper names are overloaded and cannot be passed tostd::transform without a cast to resolve a function overloading ambiguity, e.g.std::transform(string.begin(),string.end(),result.begin(), (int (*)(int))std::tolower);std::string only, result is stored in stringresult which is at least as long asstring, and may or may not bestring itselfstr::to_lowercase method.str::replace method.str::chars method iterates over code points, thestd::iter::Iterator::rev method on reversible iterators (std::iter::DoubleEndedIterator) creates a reversed iterator, and thestd::iter::Iterator::collect method consumes the iterator and creates a collection (which here is specified as aString with theturbofish syntax) from the iterator's elements.str::rfind method.str::split andstr::rsplit methods.startpos can be negative, which indicates to start that number of places before the end of the string.numChars can be negative, which indicates to end that number of places before the end of the string.startpos cannot be negative, use* - startpos to indicate to start that number of places before the end of the string.numChars cannot be negative, use* - numChars to indicate to end that number of places before the end of the string.endpos can be negative, which indicates to end that number of places before the end of the string.std::string only, result is stored in stringresult which is at least as long asstring, and may or may not bestring itselfstr::to_uppercase method returns a newly allocatedString with any lowercase characters changed to uppercase ones following the Unicode rules.str::trim method returns a reference to the original&str.