Comparison of programming languages (string functions)

"String functions" redirects here. For string functions in formal language theory, see String operations.

Programming language comparisons
General comparison
Basic syntax
Basic instructions
Arrays
Associative arrays
String operations
String functions
List comprehension
Object-oriented programming
Object-oriented constructors
Database access
Database RDBMS

Evaluation strategy
List of "hello world" programs

ALGOL 58's influence on ALGOL 60
ALGOL 60: Comparisons with other languages
Comparison of ALGOL 68 and C++
ALGOL 68: Comparisons with other languages
Compatibility of C and C++
Comparison of Pascal and Borland Delphi
Comparison of Object Pascal and C
Comparison of Pascal and C
Comparison of Java and C++
Comparison of C# and Java
Comparison of C# and Visual Basic .NET
This box: view · talk · edit

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

Most computer 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.

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

eg. 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)

Here is a list of common string functions which are found in other languages. Any other equivalent functions used by other languages are also listed. 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, Pascal, Object Pascal (Delphi)	1
string[i]	C, C++, C#, D, FreeBASIC, Go, Python¹, PHP, Ruby¹, Windows PowerShell	0
string{i}	PHP (deprecated in 5.3)	0
string(i)	Ada	≥1
Mid(string,i,1)	VB	1
string.Chars(i)	VB.NET	0
string(i:i)	Fortran	1
string.charAt(i)	Java, JavaScript	0
string.[i]	OCaml, F#	0
String.sub (string, i)	Standard ML	0
string !! i	Haskell	0
(string-ref string i)	Scheme	0
(char string i)	Common Lisp	0
substr(string, i, 1)	Perl¹	0
string.at(i)	C++ (`std::string` only) (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)	Lua¹	1
string at: i	Smalltalk (w/ bounds checking)	1
string index string i	Tcl	0

In this language, the index can be negative, which then indicates the number of places before the end of the string.

{ Example in Pascal }
var 
  MyStr: string = 'Hello, World';
  MyChar: Char;
begin
  MyChar := MyStr[2];         // 'e'

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

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

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

' Example in Visual Basic
GetChar("Hello, World", 2) '  "e"

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

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

Compare (integer result)

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 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.

Format	Languages
IF string1<string2 THEN -1 ELSE ABS (string1>string2) FI	ALGOL 68
cmp(string1, string2)	Python (before 3.0 only)
int(string1 > string2) - int(string1 < string2)	Python (since 3.0)
strcmp(string1, string2)	C, C++ (`char *` only), PHP
std.string.cmp(string1, string2)	D
StrComp(string1, string2)	VB, Object Pascal (Delphi)
string1 cmp string2	Perl
string1 <=> string2	Ruby
string1.compare(string2)	C++ (`std::string` only)
compare(string1, string2)	REXX
CompareStr(string1, string2)	Pascal, Object Pascal (Delphi)
string1.compareTo(string2)	Java
string1.CompareTo(string2)	VB .NET, C#, F#
(string= string1 string2)	Common Lisp
(string-compare string1 string2 p< p= p>)	Scheme (SRFI 13)
compare string1 string2	OCaml
String.compare (string1, string2)	Standard ML (returns LESS, EQUAL, or GREATER)
compare string1 string2	Haskell (returns LT, EQ, or GT)
[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 (returns `.TRUE.` or `.FALSE.`)
string1.localeCompare(string2)	JavaScript
bytes.Compare([]byte(string1), []byte(string2))	Go
string compare ?-nocase? ?-length int? string1 string2	Tcl

# Example in Python
cmp("hello", "world")      # returns -1

/** 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	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 op string2, where op can be any of =, <>, <, >, <= and >=	Pascal, Object Pascal (Delphi), OCaml, Standard ML, VB, VB .NET, F#
string1 op string2, where op can be any of =, /=, ≠, <, >, <=, ≤ and ≥; Also: EQ, NE, LT, LE, GE and GT	ALGOL 68
(stringX? string1 string2), where X can be any of =, -ci=, <, -ci<, >, -ci>, <=, -ci<=, >= and -ci>= (operators starting with '-ci' are case-insensitive)	Scheme
(stringX string1 string2), where X can be any of =, -ci=, <>, -ci<>, <, -ci<, >, -ci>, <=, -ci<=, >= and -ci>= (operators starting with '-ci' are case-insensitive)	Scheme (SRFI 13)
(stringX string1 string2), where X can be any of =, -equal, /=, -not-equal, <, -lessp, >, -greaterp, <=, -not-greaterp, >= and -not-lessp (the verbal operators are case-insensitive)	Common Lisp
string1 op string2, where op can be any of =, \=, <, >, <= and >=	REXX
string1 op string2, where op can be any of =, /=, <, >, <= and >=	Ada
string1 op string2, where op can be any of ==, /=, <, >, =< and >=	Erlang
string1 op string2, where op can be any of ==, /=, <, >, <= and >=	Haskell
string1 op string2, where op can be any of eq, ne, lt, gt, le and ge	Perl
string1 op string2, where op can be any of ==, !=, <, >, <= and >=	C++ (`std::string` only), C#, D, Go, JavaScript, Python, PHP, Ruby
string1 op string2, 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
string1 op string2, where op can be any of ==, ~=, <, >, <= and >=	Lua
string1 op string2, where op can be any of =, ~=, <, >, <= and >=	Smalltalk
string1 op string2, where op can be any of ==, /=, <, >, <= and >=; Also: .EQ., .NE., .LT., .LE., .GT. and .GE.	Fortran

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

# 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

Main article: Concatenation

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
string1 & string2	Ada, FreeBASIC, VB, VB .NET
strcat(string1, string2)	C, C++ (`char ` only; modifies string1*, which must have enough space to store the result)
string1 . string2	Perl, PHP
string1 + string2	ALGOL 68, C++ (`std::string` only), C#, FreeBASIC, Go, Pascal, Object Pascal (Delphi), Java, JavaScript, Windows PowerShell, Python, Ruby, F#, Turing, VB
string1 ~ string2	D
(string-append string1 string2)	Scheme
(concatenate 'string string1 string2)	Common Lisp
string1 \|\| string2	REXX, SQL
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
string1 string2	SNOBOL

{ 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"

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

Format	Languages
string_in_string(string, loc int, substring)	ALGOL 68
ContainsStr(string, substring)	Object Pascal (Delphi)
string.Contains(substring)	C#, VB .NET, Windows PowerShell, F#
string.contains(substring)	Java (1.5+)
string.indexOf(substring) >= 0	JavaScript
strpos(string, substring) !== false	PHP
substring in string	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)
String.isSubstring substring string	Standard ML
(search substring string)	Common Lisp

¢ 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

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

Equality

Tests if two strings are equal. See also #Compare and #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
string1 == string2	Python, C++(`std::string` only), C# Go, JavaScript (similarity), PHP (similarity), Ruby, Erlang, Haskell, Lua, D
string1 === string2	JavaScript, PHP
string1 == string2 or string1 .EQ. string2	Fortran
strcmp(string1, string2) == 0	C, C++ (`char *` only)
(string=? string1 string2)	Scheme
(string= string1 string2)	Common Lisp
string1 = string2	ALGOL 68, Ada, Object Pascal (Delphi), OCaml, Pascal, REXX, Standard ML, VB, VB .NET, F#, Smalltalk
test string1 = string2, or [ string1 = string2 ]	Bourne Shell
string1 eq string2	Perl
string1.equals(string2)	Java
string1 -eq string2, or [string]::Equals(string1, string2)	Windows PowerShell
[string1 isEqualToString:string2], or [string1 isEqual:string2]	Objective-C (`NSString *` only)

// Example in C#
"hello" == "world"           // returns false

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

# Example in Windows PowerShell
"hello" -eq "world"          #  returns false

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
index(string,substring)	AWK	returns 0
index(string,substring«,startpos»)	Perl	returns -1
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.find(string, substring)	D	returns -1
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++ (`std::string` only)	returns std::string::npos
string.find(substring«,startpos«,endpos»»)	Python	returns -1
string.index(substring«,startpos«,endpos»»)	Python	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
List.findIndex (List.isPrefixOf substring) (List.tails string)	Haskell (returns Just 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)

; Examples in Common Lisp
(search "e" "Hello mate")             ;  returns 1
(search "z" "word")                   ;  returns NIL

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

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

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

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 BOOL: TRUE or FALSE, and position in REF INT pos.
instr(string, any char«,startpos») (char, can contain more them one char, in witch case the position of the first appearence of any of them is returned.)	FreeBASIC	returns 0
strchr(string,char)	C, C++ (`char *` only, returns pointer to character)	returns NULL
std.string.find(string, dchar)	D	returns -1
string.find(char«,startpos»)	C++ (`std::string` only)	returns std::string::npos
strings.IndexRune(string,char)	Go	returns -1
string.indexOf(char«,startpos»)	Java	returns -1
string.IndexOf(char«,startpos«, charcount»»)	VB .NET, C#, Windows PowerShell, F#	returns -1
(position char string)	Common Lisp	returns NIL
List.elemIndex char string	Haskell (returns Just index)	returns Nothing
String.index string char	OCaml	raises Not_found
position = SCAN (string, set «, back» «, kind») or position = VERIFY (string, set «, back» «, kind»)^[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

// 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,^[1] while VERIFY returns the position of the first character that does not belong to the set.^[2]

Format

Definition	format(formatstring, items) returns string
Description	Returns the formatted string representation of one or more items. See sprintf for more information.

Format	Languages
associate(file, string); putf(file, $formatstring$, items)	ALGOL 68
Format(item, formatstring)	VB
sprintf(formatstring, items)	Perl, PHP, Ruby
io_lib:format(formatstring, items)	Erlang
sprintf(outputstring, formatstring, items)	C, C++ (`char *` only)
std.string.format(formatstring, items)	D
Format(formatstring, items)	Object Pascal (Delphi)
fmt.Sprintf(formatstring, items)	Go
printf -v outputstring formatstring items	Bash shell
formatstring % (items)	Python, Ruby
formatstring.format(items)	Python 3.x (format specification is different from printf)
Printf.sprintf formatstring items	OCaml (formatstring must be a fixed literal at compile time for it to have the correct type), F#
Text.Printf.printf formatstring items	Haskell (GHC)
String.format(formatstring, items)	Java
String.Format(formatstring, items)	VB .NET, C#, F#
(format formatstring items)	Scheme (SRFI 28)
(format nil formatstring items)	Common Lisp
formatstring -f items	Windows PowerShell
[NSString stringWithFormat:formatstring, items]	Objective-C (`NSString *` only)
string.format(formatstring, items) (formatstring):format(items)	Lua
WRITE (outputstring, formatstring) items	Fortran

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

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

Inequality

Tests if two strings are not equal. See also #Equality.

Format	Languages
string1 ne string2, or string1 NE string2	ALGOL 68 - note: the operator "ne" is literally in bold type-font.
string1 /= string2	ALGOL 68, Ada, Erlang, Fortran, Haskell
string1 <> string2	VB, VB .NET, Pascal, Object Pascal (Delphi), OCaml, PHP, Standard ML, F#
string1 ne string2	Perl
(string<> string1 string2)	Scheme (SRFI 13)
(string/= string1 string2)	Common Lisp
string1 != string2	C++ (`std::string` only), C#, Go, JavaScript (not similar), PHP (not similar), Python, Ruby, D
string1 !== string2	JavaScript, PHP
string1 \= string2	REXX
test string1 != string2, or [ string1 != string2 ]	Bourne Shell
string1 -ne string2, or -not [string]::Equals(string1, string2)	Windows PowerShell
string1 ~= string2	Lua, Smalltalk

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

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

# Example in Windows PowerShell
"hello" -ne "world"   #  returns true

index

see #Find

indexof

see #Find

instr

see #Find

instrrev

see #rfind

join

Definition	join(separator, list_of_strings) joins a list of strings 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
implode(separator, array_of_strings)	PHP
separator.join(sequence_of_strings)	Python
array_of_strings.join(separator)	Ruby, JavaScript
(string-join array_of_strings separator)	Scheme (SRFI 13)
(format nil "~{~a~^separator~}" array_of_strings)	Common Lisp
strings.Join(array_of_strings, separator)	Go
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#
&{$OFS=$separator; "$array_of_strings"}, or array_of_strings -join separator	Windows PowerShell
[array_of_strings componentsJoinedByString:separator]	Objective-C (`NSString *` only)
table.concat(table_of_strings, separator)	Lua
String streamContents: [ :stream \| collectionOfAnything asStringOn: stream delimiter: separator ]	Smalltalk (Squeak, Pharo)

// Example in C#
String.Join("-", {"a", "b", "c"})  // "a-b-c"

# Example in Perl
join( '-', ('a', 'b', 'c'));       # '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).

Format	Languages
string (string'First .. string'First + n - 1)	Ada
string:substr(string, start, length)	Erlang
Left(string,n)	VB
left(string,n)	FreeBASIC, Ingres
left(string,n «,padchar»)	REXX, Erlang
substr(string, 0, n)	AWK (changes string), Perl, PHP
string[:n]	Python
string[0, n] string[0..n - 1]	Ruby
string.substr(0,n)	C++ (`std::string` only)
string[0 .. n]	D (if n is larger than the length of the string, then in Debug mode ArrayRangeException is thrown, in Release mode, the behaviour is unspecified)
string.Substring(0,n)	VB .NET, C#, Windows PowerShell, F#
leftstr(string, n)	Pascal, Object Pascal (Delphi)
string.substring(0,n)	Java, JavaScript
(string-take string n)	Scheme (SRFI 13)
take n string	Haskell
[string substringToIndex:n]	Objective-C (`NSString *` only)
String.extract (string, n, NONE)	Standard ML
String.sub string 0 n	OCaml (if n is larger than length of string, raises Invalid_argument)
string.[..n]	F#
string.sub(string, 1, n) (string):sub(1, n)	Lua
string first: n	Smalltalk (Squeak, Pharo)
string(:n)	Fortran

/* 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 Basic
Left("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
length(string)		FreeBASIC, Ingres, Perl, Pascal, Object Pascal (Delphi), REXX, SQL
len(string)		Python, Go
length(string), string:len(string)		Erlang
Len(string)		VB
string.Length	Number of 16-bit UTF-16-encoded blocks	VB .NET, C#, Windows PowerShell, F#
string.size OR string.length	Number of bytes (Ruby lacks Unicode support)	Ruby
strlen(string)	Number of bytes	C, C++ (`char *` only), PHP
string.length()		C++ (`std::string` only)
string.length		D
string.length()	Number of 16-bit UTF-16-encoded blocks	Java
string.length		JavaScript
(string-length string)		Scheme
(length string)		Common Lisp
String.length string		OCaml
size string		Standard ML
length string	Number of Unicode codepoints	Haskell
[string length]		Objective-C (`NSString *` only)
string.len(string) (string):len() #string		Lua
string size		Smalltalk
LEN(string), or LEN_TRIM(string)		Fortran

// Examples in C#
"hello".Length;      // returns 5
"".Length;           // returns 0

# Examples in Erlang
string:len("hello"). %  returns 5
string:len("").      %  returns 0

# Examples in Perl
length("hello");     #  returns 5
length("");          #  returns 0

' Examples in Visual Basic
Len("hello")         '  returns 5
Len("")              '  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
tolower(char)	C (operates on one character)
std.string.tolower(string)	D
transform(string.begin(), string.end(), result.begin(), tolower)^[3]	C++ (`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)
lowercase(string)	Object Pascal (Delphi)
strtolower(string)	PHP
echo "string" \| tr 'A-Z' 'a-z'	Unix
string.lower()	Python
string.downcase	Ruby (only ASCII characters as Ruby lacks Unicode support)
strings.ToLower(string)	Go
(string-downcase string)	Scheme (R6RS), Common Lisp
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)
string.lower(string) (string):lower()	Lua
string asLowercase	Smalltalk
LOWER(string)	SQL

// 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 <ctype.h>
#include <stdio.h>
int main(void) {
    char string[] = "Wiki means fast?";
    int i;
    for (i = 0; i < sizeof(string) - 1; ++i) {
        /* transform characters in place, one by one */ 
        string[i] = tolower(string[i]);
    }
    puts(string);                       /* "wiki means fast?" */
    return 0;
}

mid

see #substring

partition

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
string.partition(separator)	Python, Ruby(1.9+)
lists:partition(pred, string)	Erlang
split /(separator)/, string, 2	Perl

# 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
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
string.Replace(find, replace)	VB .NET, C#, F#
str_replace(find, replace, string)	PHP
re:replace(string, find, replace, «{return, list}»)	Erlang
string.replace(find, replace)	Python, Java (1.5+)
string.replaceAll(find_regex, replace)^[4]	Java
string.gsub(find, replace)	Ruby
string =~ s/find_regex/replace/g^[4]	Perl
string.replace(find, replace, "g") or string.replace(/find_regex/g, replace)^[4]	JavaScript
echo "string" \| sed 's/find_regex/replace/g'^[4]	Unix
string.replace(find, replace), or string -replace find_regex, replace^[4]	Windows PowerShell
Str.global_replace (Str.regexp_string find) replace string	OCaml
[string stringByReplacingOccurrencesOfString:find withString:replace]	Objective-C (`NSString *` only)
string.gsub(string, find, replace) (string):gsub(find, replace)	Lua
string copyReplaceAll: find with: replace	Smalltalk (Squeak, Pharo)
string map {find replace} string	Tcl

// 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 Visual Basic
Replace("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, Haskell
lists:reverse(string)	Erlang
strrev(string)	PHP
string[::-1]	Python
(string-reverse string)	Scheme (SRFI 13)
(reverse string)	Common Lisp
string.reverse	Ruby
new StringBuilder(string).reverse().toString()	Java
std::reverse(string.begin(), string.end());	C++ (`std::string` only, modifies string)
StrReverse(string)	VB
string.Reverse().ToString()	VB .NET, C#
implode (rev (explode string))	Standard ML
string.split("").reverse().join("")	JavaScript
string.reverse(string) (string):reverse()	Lua
string reverse	Smalltalk

# Example in Perl
reverse "hello"              # 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	returns -1
strrpos(string,substring«,startpos»)	PHP	returns FALSE
string.rfind(substring«,startpos»)	C++ (`std::string` only)	returns std::string::npos
std.string.rfind(string, substring)	D	returns -1
string.rfind(substring«,startpos«, endpos»»)	Python	returns -1
string.rindex(substring«,startpos»)	Ruby	returns nil
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 NIL
[string rangeOfString:substring options:NSBackwardsSearch].location	Objective-C (`NSString *` only)	returns NSNotFound
Str.search_backward (Str.regexp_string substring) string (Str.length string - 1)	OCaml	raises Not_found
string.match(string, '.()'..substring) string:match('.()'..substring)	Lua	returns nil

; 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 Visual Basic
InStrRev("Hello mate", "e")              '  returns 10
InStrRev(5, "Hello mate", "e")           '  returns 2
InStrRev("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)	FreeBASIC, Ingres
string.substring(string.length()-n)	Java
string.substring(string.length-n, string.length)	JavaScript
right(string,n «,padchar»)	REXX, Erlang
substr(string,-n)	Perl, PHP
string[-n:]	Python
(string-take-right string n)	Scheme (SRFI 13)
string[-n..-1]	Ruby
string[$-n .. $]	D (if n is larger than length of string, then in Debug mode ArrayRangeException is thrown, and unspecified behaviour in Release mode)
String.sub string (String.length string - n) n	OCaml (if n is larger than length of string, raises Invalid_argument)
string.sub(string, -n) (string):sub(-n)	Lua
string last: n	Smalltalk (Squeak, Pharo)

/* 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 Basic
Right("sandroguidi", 3)        '  returns "idi" 
Right("sandroguidi", 100)      '  returns "sandroguidi"

// Examples in Java; extract rightmost 4 characters
String str = "CarDoor";
str.substring(str.length()-4); // returns 'Door'

rpartition

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')

slice

see #substring

split

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. 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. Opposite of join.

Format	Languages
split(/separator/, string«, limit»)	Perl
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)
TStringList.Delimiter, TStringList.DelimitedText	Object Pascal

// Example in C#
"abc,defgh,ijk".Split(',');                 // {"abc", "defgh", "ijk"}
"abc,defgh;ijk".Split(',', ';');            // {"abc", "defgh", "ijk"}

% Example in Erlang
string: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
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
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')

sprintf

see #Format

strip

see #trim

strcmp

see #Compare (integer result)

substring¹

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.

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
substr(string, startpos, numChars)	AWK (changes string), Perl^2,4, PHP^2,4
substr(string, startpos «,numChars, padChar»)	REXX
string[startpos:endpos]	Python^2,3, Go
string[startpos, numChars] string[startpos .. endpos-1] string[startpos ... endpos]	Ruby^2,3
string.slice(startpos«, endpos»)	JavaScript^2,3
string.substr(startpos«, numChars»)	C++ (`std::string` only), 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
String.sub string startpos numChars	Ocaml
substring (string, startpos, numChars)	Standard ML
string:sub_string(string, startpos, endpos) string:substr(string, startpos, numChars)	Erlang
char result[numChars+1] = ""; strncat(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^2,3
string copyFrom: startpos to: endpos	Smalltalk
string(startpos:endpos)	Fortran
SUBSTRING(string FROM startpos «FOR numChars»)	SQL

See CharAt for base of startpos/endpos.
In this language, startpos can be negative, which indicates to start that number of places before the end of the string.
In this language, endpos can be negative, which indicates to end that number of places before the end of the string.
In this language, numChars can be negative, which indicates to end that number of places before the end of the string.

// 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 "bc"
 
<source lang="text">
% Examples in Erlang
string:substr("abc", 2, 1). %  returns "b"
string:substr("abc", 2).    %  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
toupper(char)	C (operates on one character)
std.string.toupper(string)	D
transform(string.begin(), string.end(), result.begin(), toupper)^[3]	C++ (`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)
uppercase(string)	Object Pascal (Delphi)
upcase(char)	Object Pascal (Delphi) (operates on one character)
strtoupper(string)	PHP
echo "string" \| tr 'a-z' 'A-Z'	Unix
translate(string) , or UPPER variables , or PARSE UPPER VAR SrcVar DstVar	REXX
string.upper()	Python
string.upcase	Ruby (only ASCII characters as Ruby lacks Unicode support)
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)
string.upper(string) (string):upper()	Lua
string asUppercase	Smalltalk
UPPER(string)	SQL

// Example in C#
"Wiki means fast?".ToUpper();      // "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 Basic
UCase("Wiki means fast?")          '  "WIKI MEANS FAST?"

trim

Main article: Trim (programming)

trim or strip is used to remove whitespace from the beginning, end, or both beginning and end, of a string.

Notes

^ http://fortranwiki.org/fortran/show/scan
^ http://fortranwiki.org/fortran/show/verify
^ ^a ^b The transform, tolower, and toupper functions exist in the std:: namespace. You must include the <algorithm> header file for the transform function, and include the <cctype> header file for the tolower and toupper functions. In some compilers, a cast must be made to the tolower or toupper function in order to resolve a function overloading ambiguity; e.g. std::transform(string.begin(), string.end(), result.begin(), (int (*)(int))std::tolower);
^ ^a ^b ^c ^d ^e 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.

External links

Categories:

Programming language comparisons
String (computer science)

Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

Comparison of programming languages (basic instructions) — Programming language comparisons General comparison Basic syntax Basic instructions Arrays Associative arrays String operations … Wikipedia
Comparison of programming languages — Programming language comparisons General comparison Basic syntax Basic instructions Arrays Associative arrays String operations … Wikipedia
Comparison of programming languages (object-oriented programming) — Programming language comparisons General comparison Basic syntax Basic instructions Arrays Associative arrays String operations … Wikipedia
Comparison of programming languages (mapping) — Programming language comparisons General comparison Basic syntax Basic instructions Arrays Associative arrays String operations … Wikipedia
Comparison of programming languages (syntax) — Programming language comparisons General comparison Basic syntax Basic instructions Arrays Associative arrays String operations … Wikipedia
Comparison of programming languages (array) — Programming language comparisons General comparison Basic syntax Basic instructions Arrays Associative arrays String operations … Wikipedia
Comparison of programming languages (strings) — Programming language comparisons General comparison Basic syntax Basic instructions Arrays Associative arrays String operations … Wikipedia
Comparison of programming languages (list comprehension) — Programming language comparisons General comparison Basic syntax Basic instructions Arrays Associative arrays String operations … Wikipedia
String (computer science) — In formal languages, which are used in mathematical logic and theoretical computer science, a string is a finite sequence of symbols that are chosen from a set or alphabet. In computer programming, a string is traditionally a sequence of… … Wikipedia
Comparison of Pascal and C — Programming language comparisons General comparison Basic syntax Basic instructions Arrays Associative arrays String operations … Wikipedia

Academic Dictionaries and Encyclopedias

Wikipedia

Comparison of programming languages (string functions)

Contents

Common string functions (multi language reference)

CharAt

Compare (integer result)

Compare (relational operator-based, Boolean result)

Concatenation

Contains

Equality

Find

Find character

Format

Inequality

index

indexof

instr

instrrev

join

lastindexof

left

len

length

locate

Lowercase

mid

partition

replace

reverse

rfind

right

rpartition

slice

split

sprintf

strip

strcmp

substring1

Uppercase

trim

Notes

External links

Look at other dictionaries:

Share the article and excerpts

Direct link

substring¹