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. For example, the character length of "møøse" is 5 but the byte length is 7 in UTF-8 and 10 in UTF-16.
Please mark your examples with ===Character Length=== or ===Byte Length===.
4D
Byte Length
$length:=Length("Hello, world!")
ActionScript
Character Length
myStrVar.length()
Ada
Byte Length
<ada>
Str : String := "Hello World"; Length : constant Natural := Str'Size / 8;
</ada> 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.
Character Length
<ada> 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; </ada> 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.
ALGOL 68
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!
Character Length
STRING str := "hello, world"; INT length := UPB str; printf(($lx"Length of """g""" is "g(3)l$,str,length)); printf(($lx"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
AppleScript
Byte Length
count of "Hello World"
Character Length
count of "Hello World"
Or:
count "Hello World"
AWK
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($0)}
BASIC
Character Length
BASIC only supports single-byte characters. The character "ø" is converted to "°" for printing to the console and length functions, but will still output to a file as "ø".
INPUT a$ PRINT LEN(a$)
C
Byte Length
#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; char *p = (char *) string; while (*p++ != '\0') length++; return 0; }
or (for arrays of char only)
#include <stdlib.h> int main(void) { char const s[] = "Hello, world!"; size_t length = sizeof s - 1; return 0; }
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; }
TODO: non-standard library calls for system multi-byte encodings, such as _mbcslen()
C++
Byte Length
#include <string> // note: not <string.h> int main() { std::string s = "Hello, world!"; std::string::size_type length = s.length(); // option 1: In Characters/Bytes std::string::size_type size = s.size(); // option 2: In Characters/Bytes // In bytes same as above since sizeof(char) == 1 std::string::size_type bytes = s.length() * sizeof(std::string::value_type); }
For wide character strings:
#include <string> int main() { std::wstring s = L"\u304A\u306F\u3088\u3046"; std::wstring::size_type length = s.length() * sizeof(std::wstring::value_type); // in bytes }
Character Length
For wide character strings:
#include <string> int main() { std::wstring s = L"\u304A\u306F\u3088\u3046"; std::wstring::size_type length = s.length(); }
For narrow character strings and arbitrary locales:
#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.
C#
Platform: .NET
Byte Length
string s = "Hello, world!"; int blength = System.Text.Encoding.GetBytes(s).length; // In Bytes.
Character Length
string s = "Hello, world!"; int clength = s.Length; // In characters
Clean
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!"
ColdFusion
Byte Length
#len("Hello World")#
Character Length
#len("Hello World")#
Common Lisp
Byte Length
(length "Hello World")
Character Length
(length "Hello World")
Component Pascal
Byte Length
LEN("Hello, World!")
E
Character Length
"Hello World".size()
Forth
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 )
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
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 ;
Haskell
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
Character Length
The base type Char defined by the standard is already intended for (plain) Unicode characters.
strlen = length "Hello, world!"
IDL
Byte Length
Compiler: any IDL compiler should do
length = strlen("Hello, world!")
Character Length
length = strlen("Hello, world!")
J
Byte Length
# 'møøse' 7
Character Length
#7 u: 'møøse' 5
Java
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;
Character Length
Java 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.
The length method of String objects gives the number of 16-bit values used to encode a string.
String s = "Hello, world!"; int length = s.length();
Since Java 1.5, the actual number of characters can be determined by calling the codePointCount method.
String str = "\uD834\uDD2A"; //U+1D12A int length1 = str.length(); //2 int length2 = str.codePointCount(0, str.length()); //1
JavaScript
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
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
JudoScript
Byte Length
//Store length of hello world in length and print it . length = "Hello World".length();
Character Length
//Store length of hello world in length and print it . length = "Hello World".length();
Logo
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
LSE64
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
Character Length
LSE uses counted strings: arrays of characters, where the first cell contains the number of characters in the string.
" Hello world" @ , # 11
Lua
Byte Length
string="Hello world" length=#string
Character Length
string="Hello world" length=#string
Mathematica
Character length
StringLength["Hello world"]
Byte length
StringByteCount["Hello world"]
MAXScript
Character Length
"Hello world".count
mIRC Scripting Language
Byte Length
alias stringlength { echo -a Your Name is: $len($$?="Whats your name") letters long! }
Character Length
alias stringlength { echo -a Your Name is: $len($$?="Whats your name") letters long! }
Objective-C
Character Length
// Return the length in unicode characters unsigned numberOfCharacters = [@"m\xf8\xf8se" length]; // 5
Byte Length
// Return the number of bytes depending on the encoding unsigned numberOfBytes = [[@"m\xf8\xf8se" dataUsingEncoding:NSUTF8Encoding] length]; // 7
OCaml
In OCaml currently, characters are bytes.
Byte Length
String.length "Hello world";;
Character Length
String.length "Hello world";;
Perl
Byte Length
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.
Character Length
my $length = length "Hello, world!";
PHP
Byte Length
$length = strlen('Hello, world!');
Character Length
$length = mb_strlen('Hello, world!', 'UTF-8'); // or whatever encoding
PL/SQL
Byte Length
DECLARE string VARCHAR2( 50 ) := 'Hello, world!'; stringlength NUMBER; BEGIN stringlength := length( string ); END;
Character Length
DECLARE string VARCHAR2( 50 ) := 'Hello, world!'; stringlength NUMBER; BEGIN stringlength := length( string ); END;
Pop11
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);
Python
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.
# 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).
Character Length
len() returns the number of characters in a unicode string or plain ascii string. 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
Ruby
Byte Length
string="Hello world" print string.length
or
puts "Hello World".length
Character Length
require 'active_support' puts "Hello World".chars.length
Scheme
Byte Length
string-size function is only Gauche function.
(string-size "Hello world")
Character Length
string-length function is in R5RS, R6RS.
(string-length "Hello world")
Seed7
Character Length
length("Hello, world!")
Smalltalk
Byte Length
string := 'Hello, world!'. string size.
Character Length
In GNU Smalltalk:
string := 'Hello, world!". string numberOfCharacters.
requires loading the Iconv package:
PackageLoader fileInPackage: 'Iconv'
Standard ML
Byte Length
val strlen = size "Hello, world!";
Character Length
val strlen = size "Hello, world!";
Tcl
Byte Length
Basic version:
string bytelength "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 bytes is %d" $s1 [string bytelength $s1]] puts [format "length of \"%s\" in bytes is %d" $s2 [string bytelength $s2]]
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 $s2]]
Toka
Byte Length
" hello, world!" string.getLength
UNIX Shell
Byte Length
With external utilities:
string='Hello, world!' length=`echo -n "$string" | wc -c | tr -dc '0-9'` echo $length # if you want it printed to the terminal
With SUSv3 parameter expansion modifier:
string='Hello, world!' length="${#string}" echo $length # if you want it printed to the terminal
VBScript
Byte Length
LenB(string|varname)
Returns the number of bytes required to store a string in memory. Returns null if string|varname is null.
Character Length
Len(string|varname)
Returns the length of the string|varname . Returns null if string|varname is null.
XSLT
Character Length
<?xml version="1.0" encoding="UTF-8"?> ... <xsl:value-of select="string-length('møøse')" />
xTalk
Byte Length
put the length of "Hello World"
or
put the number of characters in "Hello World"
Character Length
put the length of "Hello World"
or
put the number of characters in "Hello World"
- Programming Tasks
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- AppleScript examples needing attention
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- MIRC Scripting Language examples needing attention
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- OCaml examples needing attention
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