PHP正则表达式提取特殊字符串

Question

I am trying to use regex to extract a certain syntax, in my case something like "10.100" or "20.111", in which 2 numbers are separated by dot(.) . So if I provide "a 10.100", it will extract 10.100 from the string. If I provide "a 10.100 20.101", it will extract 10.100 and 20.101.

Until now I have tried to use

preg_match('/^.*([0-9]{1,2})[^\.]([0-9]{1,4}).*$/', $message, $array);

but still no luck. Please provide any suggestion because I don't have strong regex knowledge. Thanks.

Answer 1

You may use

\b[0-9]{1,2}\.[0-9]{1,4}\b

See the regex demo.

Details:

• \b - a leading word boundary
• [0-9]{1,2} - 1 or 2 digits
• \. - a dot
• [0-9]{1,4} - 1 to 4 digits
• \b - a trailing word boundary.

If you do not care about the whole word option, just remove \b. Also, to match just 1 or more digits, you may use + instead of the limiting quantifiers. So, perhaps

[0-9]+\.[0-9]+

will also work for you.

See a PHP demo:

$re = '/[0-9]+\.[0-9]+/';
$str = 'I am trying to use regex to extract a certain syntax, in my case something like "10.100" or "20.111", in which 2 numbers are separated by dot(.) . So if I provide "a 10.100", it will extract 10.100 from the string. If I provide "a 10.100 20.101", it will extract 10.100 and 20.101.';
preg_match_all($re, $str, $matches);
print_r($matches[0]);

Output:

Array
(
    [0] => 10.100
    [1] => 20.111
    [2] => 10.100
    [3] => 10.100
    [4] => 10.100
    [5] => 20.101
    [6] => 10.100
    [7] => 20.101
)