ltrim

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

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

    Опис

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

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

    Параметри

    string

    The input string.

    characters

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

    Значення, що повертаються

    This function returns a string with whitespace stripped from the beginning of string. 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.
    • "\v" (ASCII 11 (0x0B)), a vertical tab.

    Приклади

    Приклад #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);

    ?>

    Поданий вище приклад виведе:

    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
"

    Прогляньте також

    • 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

    Improve This Page

    Learn How To Improve This Page • Submit a Pull Request • Report a Bug
    ＋add a note

    User Contributed Notes 3 notes

    up
    84
    tavi undersc 10 from yahoocom
    9 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.
    up
    23
    Usamah M dot Ali (usamah1228 at gmail dot com)
    16 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
    4
    dzek dot remove_this at dzek dot eu
    13 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.
    ＋add a note
    To Top