Regex to match URL with specific query string param

Question

I am using this regex .*\?(a\=([0-9]{3,4})) to match any URLs with the query string ?a={{a random number here}}. It should only match a query string with 3 or 4 digits

E.g.

http://www.test.com/test/test-test-test/?a=12
http://www.test.com/test-test/news/?a=734
http://www.test.com/test/?a=0987
http://www.test.com/test/test-test-test/?a=90235

My regex should match the second and third links as they contain a query string 3 or 4 digits.

I am using this tool http://www.regexpal.com/ and so far, it only highlights the second link.

score 2 · Accepted Answer · answered May 14 '16 at 13:51

Try this regex:

.+\/\?a=([0-9]{3,4})$

/.+\/\?a=([0-9]{3,4})$/gm
.+ matches any character (except newline)
Quantifier: + Between one and unlimited times, as many times as possible, giving back as needed [greedy]
\/ matches the character / literally
\? matches the character ? literally
a= matches the characters a= literally (case sensitive)
1st Capturing group ([0-9]{3,4})
[0-9]{3,4} match a single character present in the list below Quantifier: {3,4} Between 3 and 4 times, as many times as possible, giving back as needed [greedy]
0-9 a single character in the range between 0 and 9
$ assert position at end of a line