regex - PHP remove numbers in brackets -

i have string looks following in php: foo [123][bar] , i'd remove [123] string entirely end foo [bar].

another example blah [9484][m0200 blah blah blah] makes things more complicated because can't remove numbers , remove empty brackets. first set of brackets contains 3-4 digit number, , never letters, second brackets can contain anything.

any suggestions how i'd go doing this? thanks.

this regex

\[\d{3,4}\] 

will find 3-4 digit numbers inside brackets.

demo: https://regex101.com/r/kh3nz5/1

used preg_replace, http://php.net/manual/en/function.preg-replace.php, replace found instances.

echo preg_replace('~\[\d{3,4}\]~', '', 'blah [9484][m0200 blah blah blah]'); 

output:

blah [m0200 blah blah blah]

\d single number , {3,4} says @ least 3 occurrences of number , no more 4.

pages more detailed info on regexs,
http://www.rexegg.com/
http://www.regular-expressions.info/