How to match some characters with a regular expression?

Question

I have string "image(100)", i want filter the string to remove image and the parentheses then return just the number 100.

i have tried /[^image]/ and image removed, but i don't know how to remove parenthesis.

A character class is a listing of allowed/disallowed characters. It is not a series of characters. `[^image]` allows for a non `i`, `m`, `a`, `g`, or `e`. You could do `[^\d]+`, or just use PHPglue's answer below. — chris85, Apr 04 '17 at 00:39
Possible duplicate of [Remove non-numeric characters (exlcuding periods and commas) from a string](http://stackoverflow.com/questions/4949279/remove-non-numeric-characters-exlcuding-periods-and-commas-from-a-string) — Mocking, Apr 04 '17 at 01:39

StackSlave · Answer 1 · 2017-04-03T23:57:24.687

4

To just replace non-digits, with nothing, it's like this:

echo preg_replace('/\D/', '', 'image(100)');

edited Apr 03 '17 at 23:57

answered Apr 03 '17 at 23:52

StackSlave

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I'd just quantify the `\D` so you twice rather than seven times (`\D+`). – chris85 Apr 04 '17 at 00:40
Simpler than mine for sure, as long as there's no surrounding text. – miken32 Apr 04 '17 at 01:56

miken32 · Accepted Answer · 2017-09-13T17:36:02.197

1

You need to escape parentheses with a backslash, as they are special characters in regular expressions. Here I use them to capture the number and save it to the $matches array.

<?php
$str = "image(100)";
if (preg_match("/image\((\d+)\)/", $str, $matches)) {
    echo $matches[1];
}

edited Sep 13 '17 at 17:36

answered Apr 03 '17 at 23:51

miken32

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How to match some characters with a regular expression?

2 Answers2