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.

Jorge Campos · Accepted Answer · 2016-05-14 13:51:12Z

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:

Regular expression visualization

Debuggex Demo

answered May 14, 2016 at 13:51

Jorge Campos

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1 Comment

Alexis P Over a year ago

Thanks a lot! The visual representation was super helpful too. I will check the debuggex demo.

Pedro Lobito · Accepted Answer · 2016-05-14 14:08:00Z

1

a=\d{3,4}$

Regex101 Demo and Explanation

answered May 14, 2016 at 14:08

Pedro Lobito

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