preg_match_all for dates with different format

Question

I have a preg_match to get dates from a string:

preg_match_all('/\d{1,2}\.\d{1,2}\.\d{2,4}/',$myString,$dates);

This will get dates with the syntax:

01.01.2022
1.01.2022
1.1.2022
1.1.22
...

Now I have a date format like this:

25 März 2023
or
25 March 2023

How can I get this?

Answer 1

You could write the pattern as:

\b\d{1,2}(?:\.\d{1,2}\.|\h+\p{Lu}\p{Ll}+\h+)(?:\d\d|\d{4})\b

Explanation

• \b A word boundary
• \d{1,2} Match 1-2 digits
• (?: Non capture group
  • \.\d{1,2}\. Match . 1-2 digits .
  • | Or
  • \h+\p{Lu}\p{Ll}+\h+ Match any uppercase char followed by 1+ lowercase chars between 1+ horizontal whitespace chars
• ) Close the non capture group
• (?:\d\d|\d{4}) Match 2 or 4 digits
• \b A word boundary

See a regex demo and a PHP demo.

$re = '/\b\d{1,2}(?:\.\d{1,2}\.|\h+\p{Lu}\p{Ll}+\h+)(?:\d\d|\d{4})\b/u';
$str = '01.01.2022
1.01.2022
1.1.2022
1.1.22
...
Now I have a date format like this:

25 März 2023
or
25 March 2023';

preg_match_all($re, $str, $matches);
print_r($matches[0]);

Output

Array
(
    [0] => 01.01.2022
    [1] => 1.01.2022
    [2] => 1.1.2022
    [3] => 1.1.22
    [4] => 25 März 2023
    [5] => 25 March 2023
)