使用preg_match_all PHP获取字符之间的价值

Question

This is my code:

$str = 'auto_load[>=]';
$result = get_value($str);

function get_value($s) {
   if (preg_match_all('/[(=|>=|<=|~|!~|~!)]/', $str, $m)) {
       //return here...
   }
}

I want it return: ">="

(accept the return value: "=", ">=", "<=", "~", "!~" or "~!")

Somebody can help me?

Answer 1

[ is a special character used to open a character class. if you want to write a literal [ you must escape it (no need to escape ] , it isn't a special character even if it can be used to close a character class, the regex engine is smart enough to know when it is the case) :

/\[([><]?=|~!?|!~)]/