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.

Answer 1

a=\d{3,4}$

Regex101 Demo and Explanation

Answer 2

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

See it working here: https://regex101.com/r/sP0lR3/1

And as a visual representation:

Debuggex Demo