String Character Length: Difference between revisions
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==[[Forth]]== |
==[[Forth]]== |
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[[Category:Forth]] |
[[Category:Forth]] |
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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.) |
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'''Interpreter:''' ANS Forth |
'''Interpreter:''' ANS Forth |
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CREATE s ," Hello world" \ create string "s" |
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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". |
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s C@ ( -- length ) |
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binary |
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: utf8+ ( str -- str ) |
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begin |
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char+ |
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dup c@ |
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11000000 and |
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10000000 <> |
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until ; |
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decimal |
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: count-utf8 ( zstr -- n ) |
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0 |
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begin |
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swap dup c@ |
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while |
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utf8+ |
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swap 1+ |
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repeat drop ; |
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==[[Haskell]]== |
==[[Haskell]]== |
Revision as of 17:33, 16 August 2007
![Task](http://static.miraheze.org/rosettacodewiki/thumb/b/ba/Rcode-button-task-crushed.png/64px-Rcode-button-task-crushed.png)
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 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 byte length, see String Byte Length.
ActionScript
myStrVar.length()
Ada
Compiler: GCC 4.1.2
Str : String := "Hello World"; Length : constant Natural := Str'Length;
AppleScript
count of "Hello World"
AWK
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, world!" | awk '{print length($0)}'
From executable script: (prints for every line arriving on stdin)
#!/usr/bin/awk -f {print"The length of this line is "length($0)}
C
Compiler: GCC 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; 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; }
For wide character strings (usually Unicode):
#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; }
C++
Standard: ISO C++ (AKA C++98):
Compiler: g++ 4.0.2
#include <string> // note: not <string.h> int main() { std::string s = "Hello, world!"; // Always in characters == bytes since sizeof(char) == 1 std::string::size_type length = s.length(); // option 1: In Characters/Bytes std::string::size_type size = s.size(); // option 2: In Characters/Bytes }
For wide character strings:
#include <string> int main() { std::wstring s = L"\u304A\u306F\u3088\u3046"; std::wstring::size_type length = s.length(); }
C#
Platform: .NET Language Version: 1.0+
string s = "Hello, world!"; int clength = s.Length; // In characters int blength = System.Text.Encoding.GetBytes(s).length; // In Bytes.
Clean
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
#len("Hello World")#
Common Lisp
(length "Hello World")
Component Pascal
LEN("Hello, World!")
E
"Hello World".size()
Forth
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.)
Interpreter: ANS Forth
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".
binary : 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
Compiler: GHC 6.6
strlen = length "Hello, world!"
IDL
Compiler: any IDL compiler should do
length = strlen("Hello, world!")
Java
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
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
//Store length of hello world in length and print it . length = "Hello World".length();
Lua
Interpreter: Lua 5.0 or later.
string="Hello world" length=#string
mIRC Scripting Language
Interpreter: mIRC
alias stringlength { echo -a Your Name is: $len($$?="Whats your name") letters long! }
OCaml
Interpreter/Compiler: Ocaml 3.09
String.length "Hello world";;
Perl
Interpreter: Perl any 5.X
my $length = length "Hello, world!";
PHP
$length = strlen('Hello, world!');
PL/SQL
DECLARE string VARCHAR2( 50 ) := 'Hello, world!'; stringlength NUMBER; BEGIN stringlength := length( string ); END;
Python
Interpreter: Python 2.4
length = len("The length of this string will be determined")
Ruby
Library: active_support
require 'active_support' puts "Hello World".chars.length
Scheme
(string-length "Hello world")
Seed7
length("Hello, world!")
Smalltalk
string := 'Hello, world!". string size.
Standard ML
Interpreter: SML/NJ 110.60, Moscow ML 2.01 (January 2004)
Compiler: MLton 20061107
val strlen = size "Hello, world!";
Tcl
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 $s2]]
UNIX Shell
With external utilities:
Interpreter: any bourne shell
string='Hello, world!' length=`echo -n "$string" | wc -c | tr -dc '0-9'` echo $length # if you want it printed to the terminal
With SUSv3 parameter expansion modifier:
Interpreter: Almquist SHell (NetBSD 3.0), Bourne Again SHell 3.2, Korn SHell (5.2.14 99/07/13.2), Z SHell
string='Hello, world!' length="${#string}" echo $length # if you want it printed to the terminal
VBScript
Len(string|varname)
Returns the length of the string|varname Returns null if string|varname is null
xTalk
Interpreter: HyperCard
put the length of "Hello World"
or
put the number of characters in "Hello World"
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