ltrim

(PHP 4, PHP 5, PHP 7, PHP 8)

ltrim — Elimina los espacios (u otros caracteres) del inicio de un string

Descripción

function ltrim(string $string, string $characters = " \n\r\t\v\x00"): string

Elimina los espacios (u otros caracteres) del inicio de un string.

Sin el segundo parámetro, ltrim() eliminará estos caracteres:

" ": carácter SP en ASCII 0x20, un espacio ordinario.
"\t": carácter HT en ASCII 0x09, una tabulación.
"\n": carácter LF en ASCII 0x0A, un salto de línea (line feed).
"\r": carácter CR en ASCII 0x0D, un retorno de carro.
"0円": carácter NUL en ASCII 0x00, el octeto NUL.
"\v": carácter VT en ASCII 0x0B, una tabulación vertical.

Parámetros

string: El string de entrada.
characters: Opcionalmente, los caracteres a eliminar también pueden ser especificados utilizando el parámetro characters. Basta con listar todos los caracteres que deben ser eliminados. Con .., es posible especificar un rango creciente de caracteres.

Valores devueltos

Esta función devuelve un string con los espacios eliminados al inicio del string.

Ejemplos

Ejemplo #1 Ejemplo con 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);
// Elimina los caracteres de control ASCII del inicio de $binary
// (de 0 a 31, inclusive)
$clean = ltrim($binary, "\x00..\x1F");
var_dump($clean);
?>

El ejemplo anterior mostrará:

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
"

Véase también

trim() - Elimina los espacios (u otros caracteres) al inicio y al final de un string
rtrim() - Elimina los espacios (u otros caracteres) al final de un string

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User Contributed Notes 3 notes

down

tavi undersc 10 from yahoocom ¶

10 years 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.

down

Usamah M dot Ali (usamah1228 at gmail dot com) ¶

18 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).

down

dzek dot remove_this at dzek dot eu ¶

15 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.

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