I am trying to extract a number from a string. The string is a filename, will be variable in its contents, but will end with a space followed by a number.
So strings like a b 1212, a 1212. I am not sure if filenames ever end up with a whitespace at the beginning, but something like 1212 should not produce a match.
I am using so far
preg_match('#^(.)* (\d*)$#', $str, $matches);
but that returns a match for case of something like 1212.
I thought about reversing the string and doing this
preg_match('#^(\d*)(\s*)(.*)$#', strrev($str), $matches);
var_dump(strrev($matches[1]));
and checking if $matches[1] != '' and that seems to work, but I am trying to better understand regex, so that I can do this without the reverse, and figure out proper pattern for the case get number at end of string, which is always preceded by a space, and where that space in turn is always preceded but anything.
Ideas?
CodePudding user response：
You can try this approach:
preg_match("/^\S.* (\b\d )$/", $str, $matches);
echo end($matches)."\n";
For instance if you use the following variable:
$str = "1234 lkjsdhf ldjfh 1223";
The call to end($matches) will return 1223
Whereas if you use the following variable:
$str = " 1212";
call to end($matches) will remain empty.
CodePudding user response：
You may use this regex:
^\S.*\b\d $
RegEx Details:
^: Start\S: Match a non-whitespace.*: Match 0 or more of any character\b\d: Match any integer number$: End