php 如何删除字符串前后的空格？
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How to remove spaces before and after a string?
提问by tarek
I have two words spirited by space of course, and a lot of spaces before and after, what I need to do is to remove the before and after spaces without the in between once.
我当然有两个空格，前后空格很多，我需要做的就是把前后空格去掉一次，中间没有。
How can I remove the spaces before and after it?
怎么去掉前后的空格？
回答by Mihai Iorga
回答by Kaii
For completeness (as this question is tagged regex), here is a trim()reimplementation in regex:
为了完整性（因为这个问题被标记为regex），这里是trim()正则表达式的重新实现：
function preg_trim($subject) {
$regex = "/\s*(\.*)\s*/s";
if (preg_match ($regex, $subject, $matches)) {
$subject = $matches[1];
}
return $subject;
}
$words = ' my words ';
$words = preg_trim($words);
var_dump($words);
// string(8) "my words"
回答by Alexandar Lazovic
For some reason two solutions above didnt worked for me, so i came up with this solution.
出于某种原因，上面的两个解决方案对我不起作用，所以我想出了这个解决方案。
function cleanSpaces($string) {
while(substr($string, 0,1)==" ")
{
$string = substr($string, 1);
cleanSpaces($string);
}
while(substr($string, -1)==" ")
{
$string = substr($string, 0, -1);
cleanSpaces($string);
}
return $string;
}
回答by Rick
The question was about how to do it with regex, so:
问题是关于如何用正则表达式来做，所以：
$str1=~ s/^\s+|\s+$//g;
That says ^at the begining \s+(white space) |or \s+$(whitespace at the end) //gremove repeatedly. this same concept works in 'ed' (vi/vim)
也就是说^在开头\s+（空格）|或\s+$（结尾的空格）//g重复删除。同样的概念适用于 'ed' (vi/vim)
sometimes it is better just to answer the question that was asked.
有时最好只是回答提出的问题。
