如何删除前导和尾随的非字母数字字符
我希望从字符串中修剪"非字母数字，类似于 trim() 处理空格的方式.
I'm looking to "trim" non-alphanumerics from a string, similar to how trim() works with whitespace.
帮我把#str|ng# 转换成str|ng.
我可以删除尾随的非字母数字:
I can remove trailing non-alphanumerics with:
$string = preg_replace('/\W+$/', '', $string); // converts `#str|ng#` to `#str|ng`
并以:
$string = preg_replace('/^\W+/', '', $string); // converts `#str|ng#` to `str|ng#`
但我怎样才能同时完成这两项工作?
But how can I accomplish both at the same time?
尝试使用像这样的 ^\W+|\W+$ 模式:
Try using a ^\W+|\W+$ pattern like this:
$string = preg_replace('/^\W+|\W+$/', '', $string);
这将替换出现在字符串开头或结尾的任何非单词字符(请注意，这不包括下划线).| 是一个交替，它将匹配任何匹配左边模式或右边模式的字符串.
This will replace any non-word characters (note this doesn't include underscores) which appear either at the beginning or end of the string. The | is an alternation, which will match any string which matches either the pattern on the left or the pattern on the right.
如果您还需要删除下划线，请使用这样的字符类:
If you also need to remove underscores, use a character class like this:
$string = preg_replace('/^[\W_]+|[\W_]+$/', '', $string);