PHP Unconference Europe 2015

ltrim

(PHP 4, PHP 5)

ltrimStrip 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
"

See Also

  • trim() - Strip whitespace (or other characters) from the beginning and end of a string
  • rtrim() - Strip whitespace (or other characters) from the end of a string

add a note add a note

User Contributed Notes 7 notes

up
4
mroeling at exed dot nl
6 months ago
@scion4581

The problem is that the character mask (_stw in your case) isn't a literal string, but a character collection. So all characters within _stw are stripped. In your case this includes the w of weight also.
up
4
dzek dot remove_this at dzek dot eu
3 years ago
Guys, if += 0 is producing wrong values sometimes, and preg_replace is cpu consuming, then just stick to the main function described on that page, and use:
<?php
$value
= ltrim($value, '0');
?>
should be the fastest and most reliable.
I think all those comments can be misleading for begginers checking this page - it's sort of using magic tricks to reinvent the wheel.
up
1
scion4581 at mail dot ru
7 months ago
What i found and i can't get why:

$word = 'stw_weight';
echo ltrim($word, 'stw_');

output:  eight instead weight

If anybody know plz let me know
up
1
Usamah M dot Ali (usamah1228 at gmail dot com)
6 years ago
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).
up
0
juan at ecogomera dot com
10 months ago
+=0 not valid for something like 0000-5. Result is 0
up
-1
John Sherwood
8 years ago
To remove leading/trailing zeroes (example: "0123.4560"), doing a += 0 is easier than trim tricks.
up
-1
Mike
3 years ago
Keep in mind the amount of resources preg_replace() uses. 
I would suggest a simple if statement if you need to parse through large amounts of data. 
<?php
function remove_leading_zeros_from_number($number_string) {
 
$limit = 9000.1
  $temp
= $number
 
(float) $temp;
  if (
$number < $limit) {
   
$number += 0;
  } else {
   
preg_replace('~^[0]*([1-9][0-9]*)$~','$1',$number_string)
  }
}
?>

Code is untested, but probably sound.
To Top