String length

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Task
String length
You are encouraged to solve this task according to the task description, using any language you may know.

In this task, the goal is to find the character and byte length of a string. This means encodings like UTF-8 need to be handled properly, as there is not necessarily a one-to-one relationship between bytes and characters. By character, we mean an individual Unicode code point, not a user-visible grapheme containing combining characters. For example, the character length of "møøse" is 5 but the byte length is 7 in UTF-8 and 10 in UTF-16.

Non-BMP code points (those between 0x10000 and 0x10FFFF) must also be handled correctly: answers should produce actual character counts in code points, not in code unit counts. Therefore a string like "𝔘𝔫𝔦𝔠𝔬𝔡𝔢" (consisting of the 7 Unicode characters U+1D518 U+1D52B U+1D526 U+1D520 U+1D52C U+1D521 U+1D522) is 7 characters long, not 14 UTF-16 code units; and it is 28 bytes long whether encoded in UTF-8 or in UTF-16.

Please mark your examples with ===Character Length=== or ===Byte Length===. If your language is capable of providing the string length in graphemes, mark those examples with ===Grapheme Length===. For example, the string "J̲o̲s̲é̲" ("J\x{332}o\x{332}s\x{332}e\x{301}\x{332}") has 4 user-visible graphemes, 9 characters (code points), and 14 bytes when encoded in UTF-8.

Contents

[edit] 4D

[edit] Byte Length

$length:=Length("Hello, world!")

[edit] ActionScript

[edit] Character Length

myStrVar.length()

[edit] Ada

Works with: GCC version 4.1.2

[edit] Byte Length

Str    : String := "Hello World";
Length : constant Natural := Str'Size / 8;

The 'Size attribute returns the size of an object in bits. Provided that under "byte" one understands an octet of bits, the length in "bytes" will be 'Size divided to 8. Note that this is not necessarily the machine storage unit. In order to make the program portable, System.Storage_Unit should be used instead of "magic number" 8. System.Storage_Unit yields the number of bits in a storage unit on the current machine. Further, the length of a string object is not the length of what the string contains in whatever measurement units. String as an object may have a "dope" to keep the array bounds. In fact the object length can even be 0, if the compiler optimized the object away. So in most cases "byte length" makes no sense in Ada.

[edit] Character Length

Latin_1_Str    : String           := "Hello World";
UCS_16_Str     : Wide_String      := "Hello World";
Unicode_Str    : Wide_Wide_String := "Hello World";
Latin_1_Length : constant Natural := Latin_1_Str'Length;
UCS_16_Length  : constant Natural := UCS_16_Str'Length;
Unicode_Length : constant Natural := Unicode_Str'Length;

The attribute 'Length yields the number of elements of an array. Since strings in Ada are arrays of characters, 'Length is the string length. Ada supports strings of Latin-1, UCS-16 and full Unicode characters. In the example above character length of all three strings is 11. The length of the objects in bits will differ.

[edit] Aime

[edit] Byte Length

length("Hello, World!")

[edit] ALGOL 68

[edit] Bits and Bytes Length

BITS bits := bits pack((TRUE, TRUE, FALSE, FALSE)); # packed array of BOOL #
BYTES bytes := bytes pack("Hello, world"); # packed array of CHAR #
print((
  "BITS and BYTES are fixed width:", new line,
  "bits width:", bits width, ", max bits: ", max bits, ", bits:", bits, new line,
  "bytes width: ",bytes width, ", UPB:",UPB STRING(bytes), ", string:", STRING(bytes),"!", new line
))

Output: 

BITS and BYTES are fixed width:
bits width:        +32, max bits: TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT, bits:TTFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
bytes width:         +32, UPB:        +32, string:Hello, world!

[edit] Character Length

STRING str := "hello, world";
INT length := UPB str;
printf(($"Length of """g""" is "g(3)l$,str,length));
 
printf(($l"STRINGS can start at -1, in which case LWB must be used:"l$));
STRING s := "abcd"[@-1];
print(("s:",s, ", LWB:", LWB s, ", UPB:",UPB s, ", LEN:",UPB s - LWB s + 1))

Output: 

Length of "hello, world" is +12
STRINGS can start at -1, in which case LWB must be used:
s:abcd, LWB:         -1, UPB:         +2, LEN:         +4

[edit] AppleScript

[edit] Byte Length

This example may be incorrect due to a recent change in the task requirements or a lack of testing. Please verify it and remove this message. If the example does not match the requirements or does not work, replace this message with Template:incorrect or fix the code yourself. 
count of "Hello World"

Mac OS X 10.5 (Leopard) includes AppleScript 2.0 which uses only Unicode (UTF-16) character strings. This example has not been tested and may not work on previous versions of AppleScript. 

set inString to "Hello World" as Unicode text
set byteCount to 0
set idList to id of inString
 
repeat with incr in idList
  set byteCount to byteCount + 2
  if incr as integer > 65535 then
    set byteCount to byteCount + 2
  end if
end repeat
 
byteCount

[edit] Character Length

count of "Hello World"

Or: 

count "Hello World"

[edit] AutoHotkey

[edit] Character Length

Msgbox % StrLen("Hello World")

Or: 

String := "Hello World"
StringLen, Length, String
Msgbox % Length

[edit] AWK

[edit] Byte Length

From within any code block: 

w=length("Hello, world!")      # static string example
x=length("Hello," s " world!") # dynamic string example
y=length($1)                   # input field example
z=length(s)                    # variable name example

Ad hoc program from command line: 

 echo "Hello, wørld!" | awk '{print length($0)}'   # 14

From executable script: (prints for every line arriving on stdin) 

#!/usr/bin/awk -f
{print"The length of this line is "length($0)}

[edit] Batch File

[edit] Byte Length

@echo off
setlocal enabledelayedexpansion
call :length %1 res
echo length of %1 is %res%
goto :eof
 
:length
set str=%~1
set cnt=0
:loop
if "%str%" equ "" (
	set %2=%cnt%
	goto :eof
	)
set str=!str:~1!
set /a cnt = cnt + 1
goto loop

[edit] BASIC

[edit] Character Length

Works with: QBasic
Works with: Liberty BASIC
Works with: PowerBASIC version PB/CC, PB/DOS

BASIC only supports single-byte characters. The character "ø" is converted to "°" for printing to the console and length functions, but will still output to a file as "ø". 

 INPUT a$
 PRINT LEN(a$)

[edit] ZX Spectrum Basic

The ZX Spectrum needs line numbers: 

10 INPUT a$
20 PRINT LEN(a$)

[edit] BBC BASIC

[edit] Character Length

      INPUT text$
      PRINT LEN(text$)

[edit] Byte Length

Works with: BBC BASIC for Windows
      CP_ACP = 0
      CP_UTF8 = &FDE9
 
      textA$ = "møøse"
      textW$ = "                 "
      textU$ = "                 "
 
      SYS "MultiByteToWideChar", CP_ACP, 0, textA$, -1, !^textW$, LEN(textW$)/2 TO nW%
      SYS "WideCharToMultiByte", CP_UTF8, 0, textW$, -1, !^textU$, LEN(textU$), 0, 0
      PRINT "Length in bytes (ANSI encoding) = " ; LEN(textA$)
      PRINT "Length in bytes (UTF-16 encoding) = " ; 2*(nW%-1)
      PRINT "Length in bytes (UTF-8 encoding) = " ; LEN($$!^textU$)

Output: 

Length in bytes (ANSI encoding) = 5
Length in bytes (UTF-16 encoding) = 10
Length in bytes (UTF-8 encoding) = 7

[edit] Bracmat

The solutions work with UTF-8 encoded strings.

[edit] Byte Length

(ByteLength=
  length
.   @(!arg:? [?length)
  & !length
);
 
out$ByteLength$𝔘𝔫𝔦𝔠𝔬𝔡𝔢

Answer: 

28

[edit] Character Length

(CharacterLength=
  length c 
.     0:?length
    & @( !arg
       :   ?
           ( %?c
           & utf$!c:?k
           & 1+!length:?length
           & ~
           )
           ?
       )
  | !length
);
 
out$CharacterLength$𝔘𝔫𝔦𝔠𝔬𝔡𝔢

Answer: 

7

An improved version scans the input string character wise, not byte wise. Thus many string positions that are deemed not to be possible starting positions of UTF-8 are not even tried. The patterns [!p and [?p implement a ratchet mechanism. [!p indicates the start of a character and [?p remembers the end of the character, which becomes the start position of the next byte. 

(CharacterLength=
  length c p
.     0:?length:?p
    & @( !arg
       :   ?
           ( [!p %?c
           & utf$!c:?k
           & 1+!length:?length
           )
           ([?p&~)
           ?
       )
  | !length
);

[edit] C

[edit] Byte Length

Works with: ANSI C
Works with: GCC version 3.3.3
#include <string.h>
 
int main(void) 
{
  const char *string = "Hello, world!";
  size_t length = strlen(string);
 
  return 0;
}

or by hand: 

int main(void) 
{
  const char *string = "Hello, world!";
  size_t length = 0;
 
  const char *p = string;
  while (*p++ != '\0') length++;                                         
 
  return 0;
}

or (for arrays of char only) 

#include <stdlib.h>
 
int main(void)
{
  char s[] = "Hello, world!";
  size_t length = sizeof s - 1;
 
  return 0;
}

[edit] Character Length

For wide character strings (usually Unicode uniform-width encodings such as UCS-2 or UCS-4): 

#include <stdio.h>
#include <wchar.h>
 
int main(void) 
{
   wchar_t *s = L"\x304A\x306F\x3088\x3046"; /* Japanese hiragana ohayou */
   size_t length;
 
   length = wcslen(s);
   printf("Length in characters = %d\n", length);
   printf("Length in bytes      = %d\n", sizeof(s) * sizeof(wchar_t));
 
   return 0;
}

[edit] Dealing with raw multibyte string

Following code is written in UTF-8, and environment locale is assumed to be UTF-8 too. Note that "møøse" is here directly written in the source code for clarity, which is not a good idea in general. mbstowcs(), when passed NULL as the first argument, effectively counts the number of chars in given string under current locale. 

#include <stdio.h>
#include <stdlib.h>
#include <locale.h>
 
int main()
{
	setlocale(LC_CTYPE, "");
	char moose[] = "møøse";
	printf("bytes: %d\n", sizeof(moose) - 1);
	printf("chars: %d\n", (int)mbstowcs(0, moose, 0));
 
	return 0;
}
output
bytes: 7
chars: 5

[edit] C++

[edit] Byte Length

Works with: ISO C++
Works with: g++ version 4.0.2
#include <string> // (not <string.h>!)
using std::string;
 
int main()
{
  string s = "Hello, world!";
  string::size_type length = s.length(); // option 1: In Characters/Bytes
  string::size_type size = s.size();     // option 2: In Characters/Bytes
  // In bytes same as above since sizeof(char) == 1
  string::size_type bytes = s.length() * sizeof(string::value_type); 
}

For wide character strings: 

#include <string>
using std::wstring;
 
int main()
{
  wstring s = L"\u304A\u306F\u3088\u3046";
  wstring::size_type length = s.length() * sizeof(wstring::value_type); // in bytes
}

[edit] Character Length

Works with: C++98
Works with: g++ version 4.0.2

For wide character strings: 

#include <string>
using std::wstring;
 
int main()
{
  wstring s = L"\u304A\u306F\u3088\u3046";
  wstring::size_type length = s.length();
}

For narrow character strings:

Works with: C++11
Works with: clang++ version 3.0
#include <iostream>
#include <codecvt>
int main()
{
    std::string utf8 = "\x7a\xc3\x9f\xe6\xb0\xb4\xf0\x9d\x84\x8b"; // U+007a, U+00df, U+6c34, U+1d10b
    std::cout << "Byte length: " << utf8.size() << '\n';
    std::wstring_convert<std::codecvt_utf8<char32_t>, char32_t> conv;
    std::cout << "Character length: " << conv.from_bytes(utf8).size() << '\n';
}
Works with: C++98
Works with: g++ version 4.1.2 20061115 (prerelease) (SUSE Linux)
#include <cwchar>  // for mbstate_t
#include <locale>
 
// give the character length for a given named locale
std::size_t char_length(std::string const& text, char const* locale_name)
{
  // locales work on pointers; get length and data from string and
  // then don't touch the original string any more, to avoid
  // invalidating the data pointer
  std::size_t len = text.length();
  char const* input = text.data();
 
  // get the named locale
  std::locale loc(locale_name);
 
  // get the conversion facet of the locale
  typedef std::codecvt<wchar_t, char, std::mbstate_t> cvt_type;
  cvt_type const& cvt = std::use_facet<cvt_type>(loc);
 
  // allocate buffer for conversion destination
  std::size_t bufsize = cvt.max_length()*len;
  wchar_t* destbuf = new wchar_t[bufsize];
  wchar_t* dest_end;
 
  // do the conversion
  mbstate_t state = mbstate_t();
  cvt.in(state, input, input+len, input, destbuf, destbuf+bufsize, dest_end);
 
  // determine the length of the converted sequence
  std::size_t length = dest_end - destbuf;
 
  // get rid of the buffer
  delete[] destbuf;
 
  // return the result
  return length;
}

Example usage (note that the locale names are OS specific): 

#include <iostream>
 
int main()
{
  // Tür (German for door) in UTF8
  std::cout << char_length("\x54\xc3\xbc\x72", "de_DE.utf8") << "\n"; // outputs 3
 
  // Tür in ISO-8859-1
  std::cout << char_length("\x54\xfc\x72", "de_DE") << "\n"; // outputs 3
}

Note that the strings are given as explicit hex sequences, so that the encoding used for the source code won't matter.

[edit] C#

Platform: .NET

Works with: C # version 1.0+

[edit] Character Length

string s = "Hello, world!";
int characterLength = s.Length;

[edit] Byte Length

Strings in .NET are stored in Unicode. 

using System.Text;
 
string s = "Hello, world!";
int byteLength = Encoding.Unicode.GetByteCount(s);

To get the number of bytes that the string would require in a different encoding, e.g., UTF8: 

int utf8ByteLength = Encoding.UTF8.GetByteCount(s);

[edit] Clean

[edit] Byte Length

Clean Strings are unboxed arrays of characters. Characters are always a single byte. The function size returns the number of elements in an array. 

import StdEnv
 
strlen :: String -> Int
strlen string = size string 
 
Start = strlen "Hello, world!"

[edit] Clojure

[edit] Byte Length

(count (.getBytes "Hello, world!")) ; 13 bytes
(count (.getBytes "π")) ; two bytes

[edit] Character length

(count "Hello, world!")

[edit] ColdFusion

[edit] Byte Length

This example may be incorrect due to a recent change in the task requirements or a lack of testing. Please verify it and remove this message. If the example does not match the requirements or does not work, replace this message with Template:incorrect or fix the code yourself. 
#len("Hello World")#

[edit] Character Length

#len("Hello World")#

[edit] Common Lisp

[edit] Byte Length

In Common Lisp, there is no standard way to examine byte representations of characters, except perhaps to write a string to a file, then reopen the file as binary. However, specific implementations will have ways to do so. For example:

Works with: SBCL
(length (sb-ext:string-to-octets "Hello Wørld"))

returns 12.

[edit] Character Length

Common Lisp represents strings as sequences of characters, not bytes, so there is no ambiguity about the encoding. The length function always returns the number of characters in a string. 

(length "Hello World")

returns 11, and 

(length "Hello Wørld")

returns 11 too.

[edit] Component Pascal

Component Pascal encodes strings in UTF-16, which represents each character with 16-bit value.

[edit] Character Length

 
MODULE TestLen;
 
	IMPORT Out;
 
	PROCEDURE DoCharLength*;
		VAR s: ARRAY 16 OF CHAR; len: INTEGER;
	BEGIN
		s := "møøse";
		len := LEN(s$);
		Out.String("s: "); Out.String(s); Out.Ln;
		Out.String("Length of characters: "); Out.Int(len, 0); Out.Ln
	END DoCharLength;
 
END TestLen.
 

A symbol $ in LEN(s$) in Component Pascal allows to copy sequence of characters up to null-terminated character. So, LEN(s$) returns a real length of characters instead of allocated by variable.

Running command TestLen.DoCharLength gives following output: 

s: møøse
Length of characters: 5

[edit] Byte Length

 
MODULE TestLen;
 
	IMPORT Out;
 
	PROCEDURE DoByteLength*;
		VAR s: ARRAY 16 OF CHAR; len, v: INTEGER;
	BEGIN
		s := "møøse";
		len := LEN(s$);
		v := SIZE(CHAR) * len;
		Out.String("s: "); Out.String(s); Out.Ln;
		Out.String("Length of characters in bytes: "); Out.Int(v, 0); Out.Ln
	END DoByteLength;
 
END TestLen.
 

Running command TestLen.DoByteLength gives following output: 

s: møøse
Length of characters in bytes: 10

[edit] D

[edit] Byte Length

import std.stdio;
 
void showByteLen(T)(T[] str) {
    writefln("Byte length: %2d - %(%02x%)",
             str.length * T.sizeof, cast(ubyte[])str);
}
 
void main() {
    string s1a = "møøse"; // UTF-8
    showByteLen(s1a);
    wstring s1b = "møøse"; // UTF-16
    showByteLen(s1b);
    dstring s1c = "møøse"; // UTF-32
    showByteLen(s1c);
    writeln();
 
    string s2a = "𝔘𝔫𝔦𝔠𝔬𝔡𝔢";
    showByteLen(s2a);
    wstring s2b = "𝔘𝔫𝔦𝔠𝔬𝔡𝔢";
    showByteLen(s2b);
    dstring s2c = "𝔘𝔫𝔦𝔠𝔬𝔡𝔢";
    showByteLen(s2c);
    writeln();
 
    string s3a = "J̲o̲s̲é̲";
    showByteLen(s3a);
    wstring s3b = "J̲o̲s̲é̲";
    showByteLen(s3b);
    dstring s3c = "J̲o̲s̲é̲";
    showByteLen(s3c);
}
Output:
Byte length:  7 - 6dc3b8c3b87365
Byte length: 10 - 6d00f800f80073006500
Byte length: 20 - 6d000000f8000000f80000007300000065000000

Byte length: 28 - f09d9498f09d94abf09d94a6f09d94a0f09d94acf09d94a1f09d94a2
Byte length: 28 - 35d818dd35d82bdd35d826dd35d820dd35d82cdd35d821dd35d822dd
Byte length: 28 - 18d501002bd5010026d5010020d501002cd5010021d5010022d50100

Byte length: 14 - 4accb26fccb273ccb265cc81ccb2
Byte length: 18 - 4a0032036f00320373003203650001033203
Byte length: 36 - 4a000000320300006f000000320300007300000032030000650000000103000032030000

[edit] Character Length

import std.stdio, std.range, std.conv;
 
void showCodePointsLen(T)(T[] str) {
    writefln("Character length: %2d - %(%x %)",
             str.walkLength(), cast(uint[])to!(dchar[])(str));
}
 
void main() {
    string s1a = "møøse"; // UTF-8
    showCodePointsLen(s1a);
    wstring s1b = "møøse"; // UTF-16
    showCodePointsLen(s1b);
    dstring s1c = "møøse"; // UTF-32
    showCodePointsLen(s1c);
    writeln();
 
    string s2a = "𝔘𝔫𝔦𝔠𝔬𝔡𝔢";
    showCodePointsLen(s2a);
    wstring s2b = "𝔘𝔫𝔦𝔠𝔬𝔡𝔢";
    showCodePointsLen(s2b);
    dstring s2c = "𝔘𝔫𝔦𝔠𝔬𝔡𝔢";
    showCodePointsLen(s2c);
    writeln();
 
    string s3a = "J̲o̲s̲é̲";
    showCodePointsLen(s3a);
    wstring s3b = "J̲o̲s̲é̲";
    showCodePointsLen(s3b);
    dstring s3c = "J̲o̲s̲é̲";
    showCodePointsLen(s3c);
}
Output:
Character length:  5 - 6d f8 f8 73 65
Character length:  5 - 6d f8 f8 73 65
Character length:  5 - 6d f8 f8 73 65

Character length:  7 - 1d518 1d52b 1d526 1d520 1d52c 1d521 1d522
Character length:  7 - 1d518 1d52b 1d526 1d520 1d52c 1d521 1d522
Character length:  7 - 1d518 1d52b 1d526 1d520 1d52c 1d521 1d522

Character length:  9 - 4a 332 6f 332 73 332 65 301 332
Character length:  9 - 4a 332 6f 332 73 332 65 301 332
Character length:  9 - 4a 332 6f 332 73 332 65 301 332

[edit] Dc

[edit] Character Length

The following code output 5, which is the length of the string "abcde" 

[abcde]Zp

[edit] E

[edit] Character Length

"Hello World".size()

[edit] Euphoria

[edit] Character Length

print(1,length("Hello World"))

[edit] F#

This is delegated to the standard .Net framework string and encoding functions.

[edit] Byte Length

open System.Text
let byte_length str = Encoding.UTF8.GetByteCount(str)

[edit] Character Length

"Hello, World".Length

[edit] Factor

[edit] Byte Length

Here are two words to compute the byte length of strings. The first one doesn't allocate new memory, the second one can easily be adapted to measure the byte length of encodings other than UTF8. 

: string-byte-length ( string -- n ) [ code-point-length ] map-sum ;
: string-byte-length-2 ( string -- n ) utf8 encode length ;

[edit] Character Length

length works on any sequece, of which strings are one. Strings are UTF8 encoded. 

length

[edit] Fantom

[edit] Byte length

A string can be converted into an instance of Buf to treat the string as a sequence of bytes according to a given charset: the default is UTF8, but 16-bit representations can also be used. 

 
fansh> c := "møøse"
møøse
fansh> c.toBuf.size   // find the byte length of the string in default (UTF8) encoding
7
fansh> c.toBuf.toHex  // display UTF8 representation
6dc3b8c3b87365  
fansh> c.toBuf(Charset.utf16LE).size    // byte length in UTF16 little-endian
10
fansh> c.toBuf(Charset.utf16LE).toHex   // display as UTF16 little-endian
6d00f800f80073006500
fansh> c.toBuf(Charset.utf16BE).size    // byte length in UTF16 big-endian
10
fansh> c.toBuf(Charset.utf16BE).toHex   // display as UTF16 big-endian
006d00f800f800730065
 

[edit] Character length

 
fansh> c := "møøse"
møøse
fansh> c.size
5
 

[edit] Forth

Works with: ANS Forth

[edit] Byte Length

Strings in Forth come in two forms, neither of which are the null-terminated form commonly used in the C standard library.

Counted string

A counted string is a single pointer to a short string in memory. The string's first byte is the count of the number of characters in the string. This is how symbols are stored in a Forth dictionary. 

CREATE s ," Hello world" \ create string "s"
s C@ ( -- length=11 )
s COUNT  ( addr len )   \ convert to a stack string, described below

Stack string

A string on the stack is represented by a pair of cells: the address of the string data and the length of the string data (in characters). The word COUNT converts a counted string into a stack string. The STRING utility wordset of ANS Forth works on these addr-len pairs. This representation has the advantages of not requiring null-termination, easy representation of substrings, and not being limited to 255 characters. 

S" string" ( addr len)
DUP .   \ 6

[edit] Character Length

The 1994 ANS standard does not have any notion of a particular character encoding, although it distinguishes between character and machine-word addresses. (There is some ongoing work on standardizing an "XCHAR" wordset for dealing with strings in particular encodings such as UTF-8.)

The following code will count the number of UTF-8 characters in a null-terminated string. It relies on the fact that all bytes of a UTF-8 character except the first have the the binary bit pattern "10xxxxxx". 

2 base !
: utf8+ ( str -- str )
  begin
    char+
    dup c@
    11000000 and
    10000000 <>
  until ;
decimal
: count-utf8 ( zstr -- n )
  0
  begin
    swap dup c@
  while
    utf8+
    swap 1+
  repeat drop ;

[edit] GAP

Length("abc");
# or same result with
Size("abc");

[edit] Go

[edit] Byte Length

package main
 
import "fmt"
 
func main() {
    m := "møøse"
    u := "𝔘𝔫𝔦𝔠𝔬𝔡𝔢"
    j := "J̲o̲s̲é̲"
    fmt.Printf("%d %s % x\n", len(m), m, m)
    fmt.Printf("%d %s %x\n", len(u), u, u)
    fmt.Printf("%d %s % x\n", len(j), j, j)
}

Output: 

7 møøse 6d c3 b8 c3 b8 73 65
28 𝔘𝔫𝔦𝔠𝔬𝔡𝔢 f09d9498f09d94abf09d94a6f09d94a0f09d94acf09d94a1f09d94a2
14 J̲o̲s̲é̲ 4a cc b2 6f cc b2 73 cc b2 65 cc 81 cc b2

[edit] Character Length

package main
 
import (
    "fmt"
    "unicode/utf8"
)
 
func main() {
    m := "møøse"
    u := "𝔘𝔫𝔦𝔠𝔬𝔡𝔢"
    j := "J̲o̲s̲é̲"
    fmt.Printf("%d %s %x\n", utf8.RuneCountInString(m), m, []rune(m))
    fmt.Printf("%d %s %x\n", utf8.RuneCountInString(u), u, []rune(u))
    fmt.Printf("%d %s %x\n", utf8.RuneCountInString(j), j, []rune(j))
}

Output: 

5 møøse [6d f8 f8 73 65]
7 𝔘𝔫𝔦𝔠𝔬𝔡𝔢 [1d518 1d52b 1d526 1d520 1d52c 1d521 1d522]
9 J̲o̲s̲é̲ [4a 332 6f 332 73 332 65 301 332]

[edit] Grapheme Length

Go does not have language or library features to recognize graphemes directly. For example, it does not provide functions implementing Unicode Standard Annex #29, Unicode Text Segmentation. It does however have convenient functions for recognizing Unicode character categories, and so an expected subset of grapheme possibilites is easy to recognize. Here is a solution recognizing the category "Mn", which includes the combining characters used in the task example. 

package main
 
import (
    "fmt"
    "unicode"
    "unicode/utf8"
)
 
func main() {
    m := "møøse"
    u := "𝔘𝔫𝔦𝔠𝔬𝔡𝔢"
    j := "J̲o̲s̲é̲"
    fmt.Printf("%d %s %x\n", grLen(m), m, []rune(m))
    fmt.Printf("%d %s %x\n", grLen(u), u, []rune(u))
    fmt.Printf("%d %s %x\n", grLen(j), j, []rune(j))
}
 
func grLen(s string) int {
    if len(s) == 0 {
        return 0
    }
    gr := 1
    _, s1 := utf8.DecodeRuneInString(s)
    for _, r := range s[s1:] {
        if !unicode.Is(unicode.Mn, r) {
            gr++
        }
    }
    return gr
}

Output: 

5 møøse [6d f8 f8 73 65]
7 𝔘𝔫𝔦𝔠𝔬𝔡𝔢 [1d518 1d52b 1d526 1d520 1d52c 1d521 1d522]
4 J̲o̲s̲é̲ [4a 332 6f 332 73 332 65 301 332]

[edit] Groovy

Calculating "Byte-length" (by which one typically means "in-memory storage size in bytes") is not possible through the facilities of the Groovy language alone. Calculating "Character length" is built into the Groovy extensions to java.lang.String.

[edit] Character Length

println "Hello World!".size()

Output: 

12

Note: The Java "String.length()" method also works in Groovy, but "size()" is consistent with usage in other sequential or composite types.

[edit] GW-BASIC

GW-BASIC only supports single-byte characters. 

10 INPUT A$
20 PRINT LEN(A$)

[edit] Haskell

[edit] Byte Length

It is not possible to determine the "byte length" of an ordinary string, because in Haskell, a string is a boxed list of unicode characters. So each character in a string is represented as whatever the compiler considers as the most efficient representation of a cons-cell and a unicode character, and not as a byte.

For efficient storage of sequences of bytes, there's Data.ByteString, which uses Word8 as a base type. Byte strings have an additional Data.ByteString.Char8 interface, which will truncate each Unicode Char to 8 bits as soon as it is converted to a byte string. However, this is not adequate for the task, because truncation simple will garble characters other than Latin-1, instead of encoding them into UTF-8, say.

There are several (non-standard, so far) Unicode encoding libraries available on Hackage. As an example, we'll use encoding-0.2, as Data.Encoding: 

import Data.Encoding
import Data.ByteString as B
 
strUTF8  :: ByteString 
strUTF8  = encode UTF8  "Hello World!"
 
strUTF32 :: ByteString 
strUTF32 = encode UTF32 "Hello World!"
 
strlenUTF8  = B.length strUTF8
strlenUTF32 = B.length strUTF32

[edit] Character Length

Works with: GHCi version 6.6
Works with: Hugs

The base type Char defined by the standard is already intended for (plain) Unicode characters. 

strlen = length "Hello, world!"

[edit] HicEst

LEN("1 character == 1 byte") ! 21

[edit] Icon and Unicon

[edit] Character Length 

   length := *s

Note: Neither Icon nor Unicon currently supports double-byte character sets.

[edit] IDL

[edit] Byte Length

This example may be incorrect due to a recent change in the task requirements or a lack of testing. Please verify it and remove this message. If the example does not match the requirements or does not work, replace this message with Template:incorrect or fix the code yourself.

Compiler: any IDL compiler should do 

length = strlen("Hello, world!")

[edit] Character Length

This example may be incorrect due to a recent change in the task requirements or a lack of testing. Please verify it and remove this message. If the example does not match the requirements or does not work, replace this message with Template:incorrect or fix the code yourself. 
length = strlen("Hello, world!")

[edit] Io

[edit] Byte Length

"møøse" sizeInBytes

[edit] Character Length

"møøse" size

[edit] J

[edit] Byte Length

   #     'møøse'
7

Here we use the default encoding for character literals (8 bit wide literals).

[edit] Character Length

   #7 u: 'møøse'
5

Here we have used 16 bit wide character literals. See also the dictionary page for u:.

[edit] Java

[edit] Byte Length

Java encodes strings in UTF-16, which represents each character with one or two 16-bit values. The length method of String objects returns the number of 16-bit values used to encode a string, so the number of bytes can be determined by doubling that number. 

String s = "Hello, world!";
int byteCount = s.length() * 2;

Another way to know the byte length of a string is to explicitly specify the charset we desire. 

String s = "Hello, world!";
int byteCountUTF16 = s.getBytes("UTF-16").length;
int byteCountUTF8  = s.getBytes("UTF-8").length;

[edit] Character Length

Java encodes strings in UTF-16, which represents each character (code point) with one or two 16-bit code units. This is a variable-length encoding scheme. The most commonly used characters are represented by one 16-bit code unit, while rarer ones like some mathematical symbols are represented by two.

The length method of String objects is not the length of that String in characters. Instead, it only gives the number of 16-bit code units used to encode a string. This is not (always) the number of Unicode characters (code points) in the string. 

String s = "Hello, world!";
int not_really_the_length = s.length(); // XXX: does not (always) count Unicode characters (code points)!

Since Java 1.5, the actual number of characters (code points) can be determined by calling the codePointCount method. 

String str = "\uD834\uDD2A"; //U+1D12A
int not_really__the_length = str.length(); // value is 2, which is not the length in characters
int actual_length = str.codePointCount(0, str.length()); // value is 1, which is the length in characters

[edit] Grapheme Length

import java.text.BreakIterator;
 
public class Grapheme {
  public static void main(String[] args) {
    printLength("møøse");
    printLength("𝔘𝔫𝔦𝔠𝔬𝔡𝔢");
    printLength("J̲o̲s̲é̲");
  }
 
  public static void printLength(String s) {
    BreakIterator it = BreakIterator.getCharacterInstance();
    it.setText(s);
    int count = 0;
    while (it.next() != BreakIterator.DONE) {
      count++;
    }
    System.out.println("Grapheme length: " + count+ " " + s);
  }
}

Output: 

Grapheme length: 5 møøse
Grapheme length: 7 𝔘𝔫𝔦𝔠𝔬𝔡𝔢
Grapheme length: 4 J̲o̲s̲é̲

[edit] JavaScript

[edit] Byte Length

JavaScript encodes strings in UTF-16, which represents each character with one or two 16-bit values. The length property of string objects gives the number of 16-bit values used to encode a string, so the number of bytes can be determined by doubling that number. 

var s = "Hello, world!";
var byteCount = s.length * 2; //26

[edit] Character Length

JavaScript encodes strings in UTF-16, which represents each character with one or two 16-bit values. The most commonly used characters are represented by one 16-bit value, while rarer ones like some mathematical symbols are represented by two.

JavaScript has no built-in way to determine how many characters are in a string. However, if the string only contains commonly used characters, the number of characters will be equal to the number of 16-bit values used to represent the characters. 

var str1 = "Hello, world!";
var len1 = str1.length; //13
 
var str2 = "\uD834\uDD2A"; //U+1D12A represented by a UTF-16 surrogate pair
var len2 = str2.length; //2

[edit] JudoScript

[edit] Byte Length

This example may be incorrect due to a recent change in the task requirements or a lack of testing. Please verify it and remove this message. If the example does not match the requirements or does not work, replace this message with Template:incorrect or fix the code yourself. 
//Store length of hello world in length and print it
. length = "Hello World".length();

[edit] Character Length

This example may be incorrect due to a recent change in the task requirements or a lack of testing. Please verify it and remove this message. If the example does not match the requirements or does not work, replace this message with Template:incorrect or fix the code yourself. 
//Store length of hello world in length and print it
. length = "Hello World".length()

[edit] LabVIEW

[edit] Byte Length

LabVIEW is using a special variant of UTF-8, so byte length == character length.


[edit] Character Length

LV strlen.png

[edit] Liberty BASIC

See BASIC

[edit]

Logo is so old that only ASCII encoding is supported. Modern versions of Logo may have enhanced character set support. 

print count "|Hello World|  ; 11
print count "møøse            ; 5
print char 248   ; ø - implies ISO-Latin character set

[edit] LSE64

[edit] Byte Length

LSE stores strings as arrays of characters in 64-bit cells plus a count. 

" Hello world" @ 1 + 8 * ,   # 96 = (11+1)*(size of a cell) = 12*8

[edit] Character Length

LSE uses counted strings: arrays of characters, where the first cell contains the number of characters in the string. 

" Hello world" @ ,   # 11

[edit] Lua

Works with: Lua version 5.0+

In Lua, a character is always the size of one byte so there is no difference between byte length and character length.

[edit] Byte Length

str = "Hello world"
length = #str

or 

str = "Hello world"
length = string.len(str)

[edit] Character Length

str = "Hello world"
length = #str

or 

str = "Hello world"
length = string.len(str)

[edit] Mathematica

[edit] Character length 

StringLength["Hello world"]

[edit] Byte length 

StringByteCount["Hello world"]

[edit] MATLAB

[edit] Character Length

>> length('møøse')
 
ans =
 
     5

[edit] Byte Length

MATLAB apparently encodes strings using UTF-16. 

>> numel(dec2hex('møøse'))
 
ans =
 
    10

[edit] Maxima

s: "the quick brown fox jumps over the lazy dog";
slength(s);
/* 43 */

[edit] MAXScript

[edit] Character Length

"Hello world".count

[edit] Metafont

Metafont has no way of handling properly encodings different from ASCII. So it is able to count only the number of bytes in a string. 

string s;
s := "Hello Moose";
show length(s);          % 11 (ok)
s := "Hello Møøse";
show length(s);          % 13 (number of bytes when the string is UTF-8 encoded,
                         % since ø takes two bytes)

Note: in the lang tag, Møøse is Latin1-reencoded, showing up two bytes (as Latin1) instead of one

[edit] mIRC Scripting Language

[edit] Byte Length

This example may be incorrect due to a recent change in the task requirements or a lack of testing. Please verify it and remove this message. If the example does not match the requirements or does not work, replace this message with Template:incorrect or fix the code yourself. 
alias stringlength { echo -a Your Name is: $len($$?="Whats your name") letters long! }

[edit] Character Length

This example may be incorrect due to a recent change in the task requirements or a lack of testing. Please verify it and remove this message. If the example does not match the requirements or does not work, replace this message with Template:incorrect or fix the code yourself.

$utfdecode() converts an UTF-8 string to the locale encoding, with unrepresentable characters as question marks. Since mIRC is not yet fully Unicode aware, entering Unicode text trough a dialog box will automatically convert it to ASCII. 

alias utf8len { return $len($utfdecode($1)) }
alias stringlength2 {
  var %name = Børje
  echo -a %name is: $utf8len(%name) characters long!
}

[edit] Modula-3

[edit] Byte Length

MODULE ByteLength EXPORTS Main;
 
IMPORT IO, Fmt, Text;
 
VAR s: TEXT := "Foo bar baz";
 
BEGIN
  IO.Put("Byte length of s: " & Fmt.Int((Text.Length(s) * BYTESIZE(s))) & "\n");
END ByteLength.

[edit] Character Length

MODULE StringLength EXPORTS Main;
 
IMPORT IO, Fmt, Text;
 
VAR s: TEXT := "Foo bar baz";
 
BEGIN
  IO.Put("String length of s: " & Fmt.Int(Text.Length(s)) & "\n");
END StringLength.

[edit] NewLISP

[edit] Character Length

(set 'Str "møøse")
(println  Str  " is " (length Str) " characters long")

[edit] Nemerle

Both examples rely on .Net faculties, so they're almost identical to C#

[edit] Character Length

def message = "How long am I anyways?";
def charlength = message.Length;

[edit] Byte Length

using System.Text;
 
def message = "How long am I anyways?";
def bytelength = Encoding.Unicode.GetByteCount(message);

[edit] Oberon-2

[edit] Byte Length

MODULE Size;
 
   IMPORT Out;
 
   VAR s: LONGINT;
      string: ARRAY 5 OF CHAR;
 
BEGIN 
   string := "Foo";
   s := LEN(string);
   Out.String("Size: ");
   Out.LongInt(s,0);
   Out.Ln;
END Size.

Output: 

Size: 5

[edit] Character Length

MODULE Length;
 
   IMPORT Out, Strings;
 
   VAR l: INTEGER;
      string: ARRAY 5 OF CHAR;
 
BEGIN 
   string := "Foo";
   l := Strings.Length(string);
   Out.String("Length: ");
   Out.Int(l,0);
   Out.Ln;
END Length.

Output: 

Length: 3

[edit] Objective-C

In order to be not ambiguous about the encoding used in the string, we explicitly provide it in UTF-8 encoding. The string is "møøse" (ø UTF-8 encoded is in hexadecimal C3 B8).

[edit] Character Length

Objective-C encodes strings in UTF-16, which represents each character (code point) with one or two 16-bit code units. This is a variable-length encoding scheme. The most commonly used characters are represented by one 16-bit code unit, while "supplementary characters" are represented by two (called a "surrogate pair").

The length method of NSString objects is not the length of that string in characters. Instead, it only gives the number of 16-bit code units used to encode a string. This is not (always) the number of Unicode characters (code points) in the string. 

// Return the length in characters
// XXX: does not (always) count Unicode characters (code points)! 
unsigned int numberOfCharacters = [@"møøse" length];  // 5

Since Mac OS X 10.6, CFString has methods for converting between supplementary characters and surrogate pair. However, the easiest way to get the number of characters is probably to encode it in UTF-32 (which is a fixed-length encoding) and divide by 4: 

int realCharacterCount = [s lengthOfBytesUsingEncoding: NSUTF32StringEncoding] / 4;

[edit] Byte Length

Objective-C encodes strings in UTF-16, which represents each character with one or two 16-bit values. The length method of NSString objects returns the number of 16-bit values used to encode a string, so the number of bytes can be determined by doubling that number. 

int byteCount = [@"møøse" length] * 2; // 10

Another way to know the byte length of a string is to explicitly specify the charset we desire. 

// Return the number of bytes depending on the encoding,
// here explicitly UTF-8
unsigned numberOfBytes =
   [@"møøse" lengthOfBytesUsingEncoding: NSUTF8StringEncoding]; // 7

[edit] Objeck

All character string elements are 1-byte in size therefore a string's byte size and length are the same.

[edit] Character Length

 
"Foo"->Size()->PrintLine();
 

[edit] Byte Length

 
"Foo"->Size()->PrintLine();
 

[edit] OCaml

In OCaml currently, characters inside the standard type string are bytes, and a single character taken alone has the same binary representation as the OCaml int (which is equivalent to a C long) which is a machine word.

For internationalization there is Camomile, a comprehensive Unicode library for OCaml. Camomile provides Unicode character type, UTF-8, UTF-16, and more...

[edit] Byte Length

Standard OCaml strings are classic ASCII ISO 8859-1, so the function String.length returns the byte length which is the character length in this encoding: 

String.length "Hello world" ;;

[edit] Character Length

While using the UTF8 module of Camomile the byte length of an utf8 encoded string will be get with String.length and the character length will be returned by UTF8.length: 

String.length "møøse"
UTF8.length "møøse"

[edit] Octave

s = "string";
stringlen = length(s)

This gives the number of bytes, not of characters. e.g. length("è") is 2 when "è" is encoded e.g. as UTF-8.

[edit] OpenEdge/Progress

The codepage can be set independently for input / output and internal operations. The following examples are started from an iso8859-1 session and therefore need to use fix-codepage to adjust the string to utf-8.

[edit] Character Length

DEF VAR lcc AS LONGCHAR.
 
FIX-CODEPAGE( lcc ) = "UTF-8".
lcc = "møøse".
 
MESSAGE LENGTH( lcc ) VIEW-AS ALERT-BOX.

[edit] Byte Length

DEF VAR lcc AS LONGCHAR.
 
FIX-CODEPAGE( lcc ) = "UTF-8".
lcc = "møøse".
 
MESSAGE LENGTH( lcc, "RAW" ) VIEW-AS ALERT-BOX.

[edit] Oz

[edit] Byte Length

{Show {Length "Hello World"}}

Oz uses a single-byte encoding by default. So for normal strings, this will also show the correct character length.

[edit] PARI/GP

[edit] Character Length

Characters = bytes in Pari; the underlying strings are C strings interpreted as US-ASCII. 

len(s)=#s; \\ Alternately, len(s)=length(s); or even len=length;

[edit] Byte Length

This works on objects of any sort, not just strings, and includes overhead. 

len(s)=sizebyte(s);

[edit] Pascal

[edit] Byte Length

 
const 
  s = 'abcdef';
begin
  writeln (length(s))
end.
 

Output: 

6

[edit] Perl

[edit] Byte Length

Works with: Perl version 5.8

Strings in Perl consist of characters. Measuring the byte length therefore requires conversion to some binary representation (called encoding, both noun and verb). 

use utf8; # so we can use literal characters like ☺ in source
use Encode qw(encode);
 
print length encode 'UTF-8', "Hello, world! ☺";
# 17. The last character takes 3 bytes, the others 1 byte each.
 
print length encode 'UTF-16', "Hello, world! ☺";
# 32. 2 bytes for the BOM, then 15 byte pairs for each character.

[edit] Character Length

Works with: Perl version 5.X
my $length = length "Hello, world!";

[edit] Grapheme Length

Since Perl 5.12, /\X/ matches an extended grapheme cluster. See "Unicode overhaul" in perl5120delta and also UAX #29.

Perl understands that "\x{1112}\x{1161}\x{11ab}\x{1100}\x{1173}\x{11af}" (한글) contains 2 graphemes, just like "\x{d55c}\x{ae00}" (한글). The longer string uses Korean combining jamo characters.

Works with: Perl version 5.12
use v5.12;
my $string = "\x{1112}\x{1161}\x{11ab}\x{1100}\x{1173}\x{11af}";  # 한글
my $len;
$len++ while ($string =~ /\X/g);
printf "Grapheme length: %d\n", $len;
Output:
Grapheme length: 2

[edit] Perl 6

[edit] Byte Length

say 'møøse'.encode('UTF-8').bytes;

[edit] Character Length

say 'møøse'.codes;

[edit] Grapheme Length

say 'møøse'.graphs;

[edit] PHP

[edit] Byte Length

$length = strlen('Hello, world!');

[edit] Character Length

$length = mb_strlen('Hello, world!', 'UTF-8'); // or whatever encoding

[edit] Grapheme Length

Works with: PHP version 5.3
$length = grapheme_strlen('Hello, world!'); // UTF-8 encoding required

[edit] PicoLisp

(let Str "møøse"
   (prinl "Character Length of \"" Str "\" is " (length Str))
   (prinl "Byte Length of \"" Str "\" is " (size Str)) )

Output: 

Character Length of "møøse" is 5
Byte Length of "møøse" is 7
-> 7

[edit] PL/I

 
declare WS widechar (13) initial ('Hello world.');
put ('Character length=', length (WS));
put skip list ('Byte length=', size(WS));
 
declare SM graphic (13) initial ('Hello world');
put ('Character length=', length(SM));
put skip list ('Byte length=', size(trim(SM));
 

[edit] PL/SQL

LENGTH calculates length using characters as defined by the input character set. LENGTHB uses bytes instead of characters. LENGTHC uses Unicode complete characters. LENGTH2 uses UCS2 code points. LENGTH4 uses UCS4 code points.

[edit] Byte Length

DECLARE
  string VARCHAR2(50) := 'Hello, world!';
  stringlength NUMBER;
BEGIN
  stringlength := LENGTHB(string);
END;

[edit] Character Length

DECLARE
  string VARCHAR2(50) := 'Hello, world!';
  stringlength NUMBER;
  unicodelength NUMBER;
  ucs2length NUMBER;
  ucs4length NUMBER;
BEGIN
  stringlength := LENGTH(string);
  unicodelength := LENGTHC(string);
  ucs2length := LENGTH2(string);
  ucs4length := LENGTH4(string);
END;

[edit] Pop11

[edit] Byte Length

Currently Pop11 supports only strings consisting of 1-byte units. Strings can carry arbitrary binary data, so user can for example use UTF-8 (however builtin procedures will treat each byte as a single character). The length function for strings returns length in bytes: 

lvars str = 'Hello, world!';
lvars len = length(str);

[edit] PostScript

[edit] Character Length

 
(Hello World) length =
11
 

[edit] PowerShell

[edit] Character Length

$s = "Hëlló Wørłð"
$s.Length

[edit] Byte Length

Translation of: C#

For UTF-16, which is the default in .NET and therefore PowerShell: 

$s = "Hëlló Wørłð"
[System.Text.Encoding]::Unicode.GetByteCount($s)

For UTF-8: 

[System.Text.Encoding]::UTF8.GetByteCount($s)

[edit] PureBasic

[edit] Character Length

 a = Len("Hello World") ;a will be 11

[edit] Byte Length

Returns the number of bytes required to store the string in memory in the given format in bytes. 'Format' can be #PB_Ascii, #PB_UTF8 or #PB_Unicode. PureBasic code can be compiled using either Unicode (2-byte) or Ascii (1-byte) encodings for strings. If 'Format' is not specified, the mode of the executable (unicode or ascii) is used.

Note: The number of bytes returned does not include the terminating Null-Character of the string. The size of the Null-Character is 1 byte for Ascii and UTF8 mode and 2 bytes for Unicode mode. 

a = StringByteLength("ä", #PB_UTF8)    ;a will be 2
b = StringByteLength("ä", #PB_Ascii)   ;b will be 1
c = StringByteLength("ä", #PB_Unicode) ;c will be 2
 

[edit] Python

[edit] 2.x

In Python 2.x, there are two types of strings: regular (8-bit) strings, and Unicode strings. Unicode string literals are prefixed with "u".

[edit] Byte Length

Works with: Python version 2.x

For 8-bit strings, the byte length is the same as the character length: 

>>> len('ascii')
5

For Unicode strings, byte length depends on the encoding. Python use 2 or 4 bytes per character internally for unicode strings, depending on how it was built. The internal representation is not interesting for the user. 

# The letter Alef
>>> len(u'\u05d0'.encode('utf-8'))
2
>>> len(u'\u05d0'.encode('iso-8859-8'))
1

Example from the problem statement: 

#!/bin/env python
# -*- coding: UTF-8 -*-
s = u"møøse"
assert len(s) == 5
assert len(s.encode('UTF-8')) == 7
assert len(s.encode('UTF-16')) == 12 # The extra character is probably a leading Unicode byte-order mark (BOM).

[edit] Character Length

Works with: Python version 2.4

len() returns the number of code units (not code points!) in a Unicode string or plain ASCII string. On a wide build, this is the same as the number of code points, but on a narrow one it is not. Python has no reliable way to get the number of characters in a string, because the answer varies according to the build.To get the length of encoded string, you have to decode it first: 

>>> len('ascii')
5
>>> len(u'\u05d0') # the letter Alef as unicode literal
1
>>> len('\xd7\x90'.decode('utf-8')) # Same encoded as utf-8 string
1
>>> len(unichr(0x1F4A9))  # shows that len() gives the wrong answer for non-BMP chars on a narrow build
2

[edit] 3.x

In Python 3.x, strings are Unicode strings.

[edit] Byte Length

Byte length depends on the encoding. Python use 2 or 4 bytes per character internally for unicode strings, depending on how it was built. The internal representation is not interesting for the user.

You can use len() to get the length of a byte sequence. To get a byte sequence from a string, you have to encode it with the desired encoding: 

# The letter Alef
>>> len('\u05d0'.encode('utf-8'))
2
>>> len('\u05d0'.encode('iso-8859-8'))
1

Example from the problem statement: 

#!/bin/env python
# -*- coding: UTF-8 -*-
s = "møøse"
assert len(s) == 5
assert len(s.encode('UTF-8')) == 7
assert len(s.encode('UTF-16')) == 12 # The extra character is probably a leading Unicode byte-order mark (BOM).

[edit] Character Length

len() returns the number of code units in a string, which can be different from the number of characters. In a narrow build, this is not a reliable way to get the number of characters. You can only easily count code points in a wide build. To get the length of an encoded byte sequence, you have to decode it first: 

>>> len('ascii')
5
>>> len(chr(0x1F4A9)) # how many code units on narrow build, how many characters on wide build only
2
>>> len('\u05d0') # the letter Alef as unicode literal
1
>>> len(b'\xd7\x90'.decode('utf-8')) # Same encoded as utf-8 byte sequence
1

[edit] R

[edit] Byte length

a <- "m\u00f8\u00f8se"
print(nchar(a, type="bytes"))  # print 7

[edit] Character length

print(nchar(a, type="chars"))  # print 5

[edit] Racket

Using this definition: 

(define str "J\u0332o\u0332s\u0332e\u0301\u0332")

on the REPL, we get the following:

[edit] Character length

-> (printf "str has ~a characters" (string-length str))
str has 9 characters

[edit] Byte length

-> (printf "str has ~a bytes in utf-8" (bytes-length (string->bytes/utf-8 str)))
str has 14 bytes in utf-8

[edit] REBOL

[edit] Byte Length

REBOL 2.x does not natively support UCS (Unicode), so character and byte length are the same. See utf-8.r for an external UTF-8 library. 

text: "møøse"
print rejoin ["Byte length for '" text "': "  length? text]

Output: 

Byte length for 'møøse': 5

[edit] Retro

[edit] Byte Length

"møøse" getLength putn

[edit] Character Length

Retro does not have built-in support for Unicode, but counting of characters can be done with a small amount of effort. 

chain: UTF8'
{{
  : utf+ ( $-$ )
    [ 1+ dup @ %11000000 and %10000000 = ] while ;
 
  : count ( $-$ )
    0 !here
    repeat dup @ 0; drop utf+ here ++ again ;
---reveal---
  : getLength ( $-n )
    count drop @here ;
}}
;chain
 
"møøse" ^UTF8'getLength putn

[edit] REXX

Classic REXX don't support Unicodes, so character and byte length are the same.
All characters (in strings) are stored as 8-bit bytes.     Indeed, everything in REXX
is stored as strings. 

/*REXX program to show lengths (in bytes/characters) for various strings*/
    /*            1         */               /*a handy over/under scale.*/
    /*   123456789012345    */
hello = 'Hello, world!'   ;    say  'length of HELLO is '   length(hello)
happy = 'Hello, world! ☺' ;    say  'length of HAPPY is '   length(happy)
jose  = 'José'            ;    say  'length of  JOSE is '   length(jose)
nill  = ''                ;    say  'length of  NILL is '   length(nill)
null  =                   ;    say  'length of  NULL is '   length(null)
sum   = 5+1               ;    say  'length of   SUM is '   length(sum)
                                       /*stick a fork in it, we're done.*/

output 

length of HELLO is  13
length of HAPPY is  15
length of  JOSE is  4
length of  NILL is  0
length of  NULL is  0
length of   SUM is  1

[edit] Ruby

[edit] Byte Length

Since Ruby 1.8.7, String#bytesize is the byte length.

Works with: Ruby version 1.8.7 or 1.9
# -*- coding: utf-8 -*-
 
puts "あいうえお".bytesize
# => 15

[edit] Character Length

Since Ruby 1.9, String#length (alias String#size) is the character length. The magic comment, "coding: utf-8", sets the encoding of all string literals in this file.

Works with: Ruby version 1.9
# -*- coding: utf-8 -*-
 
puts "あいうえお".length
# => 5
 
puts "あいうえお".size  # alias for length
# => 5

[edit] Code Set Independence

The next examples show the byte length and character length of "møøse" in different encodings.

To run these programs, you must convert them to different encodings.
  • If you use Emacs: Paste each program into Emacs. The magic comment, like -*- coding: iso-8859-1 -*-, will tell Emacs to save with that encoding.
  • If your text editor saves UTF-8: Convert the file before running it. For example:
    $ ruby -pe '$_.encode!("iso-8859-1", "utf-8")' scratch.rb | ruby
Works with: Ruby version 1.9
Program Output 
# -*- coding: iso-8859-1 -*-
s = "møøse"
puts "Byte length: %d" % s.bytesize
puts "Character length: %d" % s.length
 
Byte length: 5
Character length: 5
# -*- coding: utf-8 -*-
s = "møøse"
puts "Byte length: %d" % s.bytesize
puts "Character length: %d" % s.length
 
Byte length: 7
Character length: 5
# -*- coding: gb18030 -*-
s = "møøse"
puts "Byte length: %d" % s.bytesize
puts "Character length: %d" % s.length
 
Byte length: 11
Character length: 5

[edit] Ruby 1.8

The next example works with both Ruby 1.8 and Ruby 1.9. In Ruby 1.8, the strings have no encodings, and String#length is the byte length. In Ruby 1.8, the regular expressions knows three Japanese encodings.

  • /./n uses no multibyte encoding.
  • /./e uses EUC-JP.
  • /./s uses Shift-JIS or Windows-31J.
  • /./u uses UTF-8.

Then either string.scan(/./u).size or string.gsub(/./u, ' ').size counts the UTF-8 characters in string. 

# -*- coding: utf-8 -*-
 
class String
  # Define String#bytesize for Ruby 1.8.6.
  unless method_defined?(:bytesize)
    alias bytesize length
  end
end
 
s = "文字化け"
puts "Byte length: %d" % s.bytesize
puts "Character length: %d" % s.gsub(/./u, ' ').size

[edit] Run BASIC

input a$
print len(a$)

[edit] SAS

data _null_;
   a="Hello, World!";
   b=length(c);
   put _all_;
run;

[edit] Scheme

[edit] Byte Length

Works with: Gauche version 0.8.7 [utf-8,pthreads]

string-size function is only Gauche function. 

(string-size "Hello world")
Works with: PLT Scheme version 4.2.4
(bytes-length #"Hello world")

[edit] Character Length

Works with: Gauche version 0.8.7 [utf-8,pthreads]

string-length function is in R5RS, R6RS. 

  (string-length "Hello world")

[edit] Seed7

[edit] Character Length

length("Hello, world!")

[edit] Slate

'Hello, world!' length.

[edit] Smalltalk

[edit] Byte Length

string := 'Hello, world!'.
string size.

[edit] Character Length

In GNU Smalltalk: 

string := 'Hello, world!'.
string numberOfCharacters.

requires loading the Iconv package: 

PackageLoader fileInPackage: 'Iconv'

[edit] SNOBOL4

[edit] Byte Length 

 
	output = "Byte length: " size(trim(input))
end
 

[edit] Character Length

The example works AFAIK only with CSnobol4 by Phil Budne 

 
-include "utf.sno"
	output = "Char length: " utfsize(trim(input))
end
 


[edit] Standard ML

[edit] Byte Length

Works with: SML/NJ version 110.60
Works with: Moscow ML version 2.01
Works with: MLton version 20061107
val strlen = size "Hello, world!";

[edit] Character Length

Works with: SML/NJ version 110.74
val strlen = UTF8.size "Hello, world!";

[edit] Tcl

[edit] Byte Length

Formally, Tcl does not guarantee to use any particular representation for its strings internally (the underlying implementation objects can hold strings in at least three different formats, mutating between them as necessary) so to way to calculate the "byte length" of a string can only be done with respect to some user-selected encoding. This is done this way (for UTF-8): 

string length [encoding convertto utf-8 $theString]

Thus, we have these examples: 

set s1 "hello, world"
set s2 "\u304A\u306F\u3088\u3046"
set enc utf-8
puts [format "length of \"%s\" in bytes is %d" \
     $s1 [string length [encoding convertto $enc $s1]]]
puts [format "length of \"%s\" in bytes is %d" \
     $s2 [string length [encoding convertto $enc $s2]]]

[edit] Character Length

Basic version: 

string length "Hello, world!"

or more elaborately, needs Interpreter any 8.X. Tested on 8.4.12. 

fconfigure stdout -encoding utf-8; #So that Unicode string will print correctly
set s1 "hello, world"
set s2 "\u304A\u306F\u3088\u3046"
puts [format "length of \"%s\" in characters is %d"  $s1 [string length $s1]]
puts [format "length of \"%s\" in characters is %d"  $s2 [string length $s2]]

[edit] TI-89 BASIC

The TI-89 uses an fixed 8-bit encoding so there is no difference between character length and byte length. 

■ dim("møøse")              5

[edit] Toka

[edit] Byte Length

" hello, world!" string.getLength

[edit] Trith

[edit] Character Length

"møøse" length

[edit] Byte Length

"møøse" size

[edit] TUSCRIPT

[edit] Character Length 

 
$$ MODE TUSCRIPT
string="hello, world"
l=LENGTH (string)
PRINT "character length of string '",string,"': ",l
 

Output: 

Character length of string 'hello, world': 12

[edit] UNIX Shell

[edit] Byte Length

[edit] With external utility:

Works with: Bourne Shell
string='Hello, world!'
length=`expr "x$string" : '.*' - 1`
echo $length # if you want it printed to the terminal

[edit] With SUSv3 parameter expansion modifier:

Works with: Almquist SHell
Works with: Bourne Again SHell version 3.2
Works with: pdksh version 5.2.14 99/07/13.2
Works with: Z SHell
string='Hello, world!'
length="${#string}"
echo $length # if you want it printed to the terminal

[edit] Vala

[edit] Character Length

 
string s = "Hello, world!";
int characterLength = s.length;
 

[edit] VBA

Cf. VBScript (below).

[edit] VBScript

[edit] Byte Length

LenB(string|varname)

Returns the number of bytes required to store a string in memory. Returns null if string|varname is null.

[edit] Character Length

Len(string|varname)

Returns the length of the string|varname . Returns null if string|varname is null.

[edit] x86 Assembly

[edit] Byte Length

The following code uses AT&T syntax and was tested using AS (the portable GNU assembler) under Linux. 

 
.data
string:         .asciz "Test"
 
.text
.globl  main
 
main:
        pushl   %ebp
        movl    %esp, %ebp
 
        pushl   %edi
        xorb    %al, %al
        movl    $-1, %ecx
        movl    $string, %edi
        cld
        repne   scasb
        not     %ecx
        dec     %ecx
        popl    %edi
 
        ;; string length is stored in %ecx register                                                                                                                  
 
        leave
        ret
 

[edit] XPL0

include c:\cxpl\stdlib;
IntOut(0, StrLen("Character length = Byte length = String length = "))

Output: 

49

[edit] XSLT

[edit] Character Length

<?xml version="1.0" encoding="UTF-8"?>
...

<xsl:value-of select="string-length('møøse')" />   <!-- 5 -->

[edit] xTalk

Works with: HyperCard

[edit] Byte Length

This example may be incorrect due to a recent change in the task requirements or a lack of testing. Please verify it and remove this message. If the example does not match the requirements or does not work, replace this message with Template:incorrect or fix the code yourself. 
put the length of "Hello World"

or 

put the number of characters in "Hello World"

[edit] Character Length

This example may be incorrect due to a recent change in the task requirements or a lack of testing. Please verify it and remove this message. If the example does not match the requirements or does not work, replace this message with Template:incorrect or fix the code yourself. 
put the length of "Hello World"

or 

put the number of characters in "Hello World"

[edit] Yorick

[edit] Character Length

strlen("Hello, world!")
Retrieved from "http://rosettacode.org/mw/index.php?title=String_length&oldid=156560"
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