I need to remove multiple strings like www, ww2, www3 from the beginning of a string.
For example if the string is www3testme then I need to remove the www3 and get the testme only.
Below is the code I'm using but it's not working somehow.
$str = "www3testabc";
$str = mb_ereg_replace("^(www|www3|ww2)", "", $str);
echo $str;
It gives "3testabc" instead of "testabc".
Not sure what I'm doing wrong.
I want to use mb_ereg_replace() function only.
分享 The (www|www3|ww2) pattern contains an unanchored alternation group. Since the www, the first branch, matches www in www3testabc, the www3 is not even tested against, the regex grabs www and removes it. Thus, the number remains.
See Remember That The Regex Engine Is Eager.
You need to sort the alternatives from the longest to shortest (like ^(www3|www2|www)), or, in your case, it is much more convenient to match www at the start of the string with 0+ digits and use
$str = "www3testabc";
$str = mb_ereg_replace("^www[0-9]*", "", $str);
echo $str;
See the PHP demo.
NOTE You may use a preg_replace, too:
$str = preg_replace("/^www[0-9]*/u", "", $str);
The /^www[0-9]*/u regex will remove www and then any 0+ digits and will correctly handle Unicode input due to /u UNICODE modifier.
Note that if you have no control over the www, www2 etc. strings, and you build the pattern dynamically, you need to sort the strings by length in a descending order and then implode.
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