ltrim

(PHP 4, PHP 5)

ltrim — Strip whitespace (or other characters) from the beginning of a string

Description

string ltrim ( string $str [, string $charlist ] )

Strip whitespace (or other characters) from the beginning of a string.

Parameters

str: The input string.
charlist: You can also specify the characters you want to strip, by means of the charlist parameter. Simply list all characters that you want to be stripped. With .. you can specify a range of characters.

Return Values

This function returns a string with whitespace stripped from the beginning of str . Without the second parameter, ltrim() will strip these characters:

" " (ASCII 32 (0x20)), an ordinary space.
"\t" (ASCII 9 (0x09)), a tab.
"\n" (ASCII 10 (0x0A)), a new line (line feed).
"\r" (ASCII 13 (0x0D)), a carriage return.
"\0" (ASCII 0 (0x00)), the NUL-byte.
"\x0B" (ASCII 11 (0x0B)), a vertical tab.

Changelog

Version	Description
4.1.0	The `charlist` parameter was added.

Examples

Example #1 Usage example of ltrim()


<?php

$text = "\t\tThese are a few words :) ...  ";
$binary = "\x09Example string\x0A";
$hello  = "Hello World";
var_dump($text, $binary, $hello);

print "\n";


$trimmed = ltrim($text);
var_dump($trimmed);

$trimmed = ltrim($text, " \t.");
var_dump($trimmed);

$trimmed = ltrim($hello, "Hdle");
var_dump($trimmed);

// trim the ASCII control characters at the beginning of $binary
// (from 0 to 31 inclusive)
$clean = ltrim($binary, "\x00..\x1F");
var_dump($clean);

?>

The above example will output:

string(32) "        These are a few words :) ...  "
string(16) "    Example string
"
string(11) "Hello World"

string(30) "These are a few words :) ...  "
string(30) "These are a few words :) ...  "
string(7) "o World"
string(15) "Example string
"


I agree with Usamah M dot Ali (usamah1228 at gmail dot com)!



I think that the nomenclature of ltrim and rtrim is very poor, as it has a bias towards left-to-right writing systems!



I suggest to rather call them btrim (trim at beginning of the character stream) and etrim (trim at end of the character stream), as this would be universally true without any bias.



Honestly this issue doesn't amaze me, because it reflects the sad reality that quite a number of people, studying technical subjects, often don't receive any humanistic/general education in their curricula at all!

Usamah M dot Ali (usamah1228 at gmail dot com)
05-Feb-2008 06:42


For those who use right-to-left languages such as Arabic, Hebrew, etc., it's worth mentioning that ltrim() (which stands for left trim) & rtrim() (which stands for right trim) DO NOT work contextually. The nomenclature is rather semantically incorrect. So in an RTL script, ltrim() will trim text from the right direction (i.e. beginning of RTL strings), and rtrim() will trim text from the left direction (i.e. end of RTL strings).

John Sherwood
07-Aug-2006 03:13


To remove leading/trailing zeroes (example: "0123.4560"), doing a += 0 is easier than trim tricks.

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Last updated: Fri, 06 Nov 2009