PHP ltrim() 函数

删除字符串左侧的字符：

<?php
$str = "Hello World!";
echo $str . " ";
echo ltrim($str,"Hello");
?>

定义和用法

ltrim() 函数从字符串左侧删除空格或其他预定义字符。

ltrim( string,charlist)

Parameter	Description
string	Required. Specifies the string to check
charlist	Optional. Specifies which characters to remove from the string. If omitted, all of the following characters are removed: "\0" - NULL "\t" - tab "\n" - new line "\x0B" - vertical tab "\r" - carriage return " " - ordinary white space

删除字符串左侧的空格：

<?php
$str = " Hello World!";
echo "Without ltrim: " . $str;
echo " ";
echo "With ltrim: " . ltrim($str);
?>

上述代码的 HTML 输出将是（查看源代码）：

<!DOCTYPE html>
<html>
<body>

Without ltrim: Hello World! With ltrim: Hello World!
</body>
</html>

上述代码的浏览器输出将是：

Without ltrim: Hello World!
With ltrim: Hello World!

从字符串左侧删除换行符 (\n)：

<?php
$str = "\n\n\nHello World!";
echo "Without ltrim: " . $str;
echo " ";
echo "With ltrim: " . ltrim($str);
?>

上述代码的 HTML 输出将是（查看源代码）：

<!DOCTYPE html>
<html>
<body>

Without ltrim:

Hello World! With ltrim: Hello World!
</body>
</html>

上述代码的浏览器输出将是：

Without ltrim: Hello World!
With ltrim: Hello World!