• PHP之string之ltrim()函数使用


    ltrim

    • (PHP 4, PHP 5, PHP 7)
    • ltrim — Strip whitespace (or other characters) from the beginning of a string
    • ltrim — 删除字符串开头的空白字符(或其他字符)

    Description

    string ltrim ( string $str [, string $character_mask ] )
    //Strip whitespace (or other characters) from the beginning of a string.
    //删除字符串开头的空白字符(或其他字符)
    

    Parameters

    str

    • The input string.
    • 输入的字符串。

    character_mask

    • You can also specify the characters you want to strip, by means of the character_mask parameter. Simply list all characters that you want to be stripped. With .. you can specify a range of characters.
    • 通过参数 character_mask,你也可以指定想要删除的字符,简单地列出你想要删除的所有字符即可。使用..,可以指定字符的范围。

    Return Values

    • This function returns a string with whitespace stripped from the beginning of str. Without the second parameter, ltrim() will strip these characters:
    • 该函数返回一个删除了 str 最左边的空白字符的字符串。 如果不使用第二个参数, ltrim() 仅删除以下字符:
    • " " (ASCII 32 (0x20)), an ordinary space.普通空白字符。
    • " " (ASCII 9 (0x09)), a tab.制表符.
    • " " (ASCII 10 (0x0A)), a new line (line feed).换行符。
    • " " (ASCII 13 (0x0D)), a carriage return.回车符。
    • "" (ASCII 0 (0x00)), the NUL-byte.NUL空字节符。
    • "x0B" (ASCII 11 (0x0B)), a vertical tab.垂直制表符。

    Examples

    <?php
    /**
     * Created by PhpStorm.
     * User: zhangrongxiang
     * Date: 2018/3/4
     * Time: 下午4:37
     */
    
    //ltrim — 删除字符串开头的空白字符(或其他字符)
    
    $hello = "Hello World";
    //Hello World
    echo ltrim( $hello ) . PHP_EOL;
    //ello World
    echo ltrim( $hello, 'H' ) . PHP_EOL;
    //llo World
    echo ltrim( $hello, 'eH' ) . PHP_EOL;
    
    $text = "		These are a few words :) ...  ";
    //		These are a few words :) ...
    echo $text . PHP_EOL;
    //These are a few words :) ...
    echo ltrim( $text ) . PHP_EOL;
    //These are a few words :) ...
    echo ltrim( $text, "	" ) . PHP_EOL;
    //		These are a few words :) ...
    echo ltrim( $text, '	' ) . PHP_EOL;
    
    $binary = "x09Example stringx0A";
    //	Example string
    //
    echo $binary . PHP_EOL;
    //Example string
    //
    echo ltrim( $binary ) . PHP_EOL;
    //Example string
    //
    echo ltrim( $binary, "x00..x1F" ) . PHP_EOL;
    

    See

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  • 原文地址:https://www.cnblogs.com/zhangrxiang/p/8505116.html
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