There seems to be spaces in the string. How to delete them?

<code>$str ='                            Controllable Eu valence for photoluminescence tuning in apatite-typed';

在编码为GBK的情况下是'聽 聽 聽 聽 聽 聽 聽 聽 聽 聽 聽 聽 聽 聽Controllable Eu valence for photoluminescence tuning in apatite-typed'；

在utf-8下是'                            Controllable Eu valence for photoluminescence tuning in apatite-typed';

</code>

<code>如何去除空格？</code>

Reply content:

<code>$str ='                            Controllable Eu valence for photoluminescence tuning in apatite-typed';

在编码为GBK的情况下是'聽 聽 聽 聽 聽 聽 聽 聽 聽 聽 聽 聽 聽 聽Controllable Eu valence for photoluminescence tuning in apatite-typed'；

在utf-8下是'                            Controllable Eu valence for photoluminescence tuning in apatite-typed';

</code>

<code>如何去除空格？</code>

Use $str = preg_replace('/^[pZpC] |[pZpC] $/u','',$str);

http://php.net/manual/zh/regexp.reference.unicode.php

Used to match common character types when UTF-8 mode is selected

pC: All unicode "other"
pZ: All unicode "separator", all spaces and invisible characters

PHP merges multiple consecutive spaces:
$output = preg_replace('/s /', ' ', $input);
s matches any whitespace character, including spaces, tabs, form feeds, etc., which is equivalent to [ fnrtv].
http://php.net/manual/zh/reference.pcre.pattern.syntax.php

$str = $str.replace(/s/g,'');

Urlencode to see what character it is, (is it a space or something else)