trim() 函数可以去掉给定字符串中头尾的空白符(中间的不去除)或其它字符,这些空白符包括:
1. 空格符 : " " (ASCII 32 (0x20)
2. 水平制表符 : "\t" (ASCII 9 (0x09))
3. 换行符 : "\n" (ASCII 10 (0x0A))
4. 回车符 : "\r" (ASCII 13 (0x0D))
5. 空字符 : "\0" (ASCII 0 (0x00))
6. 垂直制表符 : \0x0B (ASCII 11 (0x0B))
函数语法如下:
[Plain Text] 纯文本查看 复制代码 string trim ( string $str [, string $charlist ] )
[PHP] 纯文本查看 复制代码 <?php
$text = "\t\thello\t";
echo $text;
print "\n";
echo trim($text, "\t");
print "\n";
print "--------------\n";
$text = "\nlinux\n";
echo $text;
echo trim($text, "\n");
print "\n";
print "--------------\n";
$text = "\x0Bworld";
echo $text;
echo $text;
echo $text;
echo $text;
print "\n";
echo trim($text, "\x0B");
print "\n";
print "--------------\n";
?> |
运行输出:
如果去掉其它字符,那么可以在第 2 个参数里指定这些要去除字符的列表,该列表的各个字符连续书写,不需要用什么符号分隔开来。注意,这也只能是去除字符串首尾的字符,而不能去除中间的字符,如下所示:
[PHP] 纯文本查看 复制代码 <?php
function _formatDir($dir) {
$dir = trim($dir);
if ($dir)
$dir = trim($dir, "\\/><").'/';
return $dir;
}
$mydir = '><home\><wwwroot/ ';
echo $mydir;
print "\n";
echo _formatDir($mydir);
print "\n";
?>
运行输出:$ php trim.php
><home\><wwwroot/
home\><wwwroot/ |