PHP 7.1.0 Released

ltrim

(PHP 4, PHP 5, PHP 7)

ltrimSupprime les espaces (ou d'autres caractères) de début de chaîne

Description

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

Supprime les espaces (ou d'autres caractères) de début de chaîne.

Liste de paramètres

str

La chaîne d'entrée.

character_mask

Il est aussi possible de spécifier les caractères à supprimer en utilisant le paramètre character_mask. Listez simplement les caractères que vous voulez supprimer dans ce paramètre. Avec .., vous pourrez spécifier des intervalles de caractères.

Valeurs de retour

Cette fonction retourne la chaîne str, après avoir supprimé les caractères invisibles de début de chaîne. Si le second paramètre charlist a été omis, ltrim() supprimera les caractères suivants :

  • " " (ASCII 32 (0x20)), un espace ordinaire.
  • "\t" (ASCII 9 (0x09)), une tabulation.
  • "\n" (ASCII 10 (0x0A)), une nouvelle ligne (line feed).
  • "\r" (ASCII 13 (0x0D)), un retour chariot (carriage return).
  • "\0" (ASCII 0 (0x00)), le caractère NUL.
  • "\x0B" (ASCII 11 (0x0B)), une tabulation verticale.

Exemples

Exemple #1 Exemple avec 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);

// Supprime les caractères de contrôle ASCII du début de $binary
// (de 0 à 31, inclusif)
$clean ltrim($binary"\x00..\x1F");
var_dump($clean);

?>

L'exemple ci-dessus va afficher :

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
"

Voir aussi

  • trim() - Supprime les espaces (ou d'autres caractères) en début et fin de chaîne
  • rtrim() - Supprime les espaces (ou d'autres caractères) de fin de chaîne

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User Contributed Notes 8 notes

up
13
tavi undersc 10 from yahoocom
1 year ago
When using a $character_mask the trimming stops at the first character that is not on that mask.

So in the $string = "Hello world" example with $character_mask = "Hdle", ltrim($hello, $character_mask) goes like this:
1. Check H from "Hello world" => it is in the $character_mask, so remove it
2. Check e from "ello world" => it is in the $character_mask, so remove it
3. Check l from "llo world" => it is in the $character_mask, so remove it
4. Check l from "lo world" => it is in the $character_mask, so remove it
5. Check o from "o world" => it is NOT in the $character_mask, exit the function

Remaining string is "o world".

I hope it helps someone as I had a confusing moment with this function.
up
5
Usamah M dot Ali (usamah1228 at gmail dot com)
8 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
1
juan at ecogomera dot com
2 years ago
+=0 not valid for something like 0000-5. Result is 0
up
1
dzek dot remove_this at dzek dot eu
5 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
0
mroeling at exed dot nl
2 years 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
-8
John Sherwood
10 years ago
To remove leading/trailing zeroes (example: "0123.4560"), doing a += 0 is easier than trim tricks.
up
-20
scion4581 at mail dot ru
2 years 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
-19
Mike
5 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.
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