如何使用Regex匹配字符串中的PHP time（）或microtime（）？

Question

I currently have a regex command which matches php time in a string:

preg_match( '/([a-z]+)_([0-9]{9,})\.jpg/i', $aName, $lMatches );

How can I modify this to also match microtime() in the same match?

Examples:

foobar_1453887550.jpg (match)

foobar_1453887620.8717.jpg (match)

foobar_123.jpg (don't match)

foobar_adsf123123.jpg (don't match)

Answer 1

Add optional group using ?:

preg_match( '/([a-z]+)_([0-9]{9,})(\.[0-9]{4,})?\.jpg/i', $aName, $lMatches );

Here (\.[0-9]{4,})? is an optional group which can present or not in your string.

Considering @trincot remark you can change optional group to (\.[0-9]+)? if ending zeroes will not present in milliseconds.

preg_match( '/([a-z]+)_([0-9]{9,})(\.[0-9]+)?\.jpg/i', $aName, $lMatches );