RegexdrillA query string parameter
A regex exercise from Regexdrill. Solve it with a pattern box with live highlighting in your browser, checked against hidden test strings, and it is checked the moment you submit.
The task
Capture the value of the id parameter of a URL in group 1. A parameter starts right after ? or &, and its value runs up to the next & or #, or to the end of the line. Parameters whose name only ends in id, like uid, do not count. The value can be empty.
What this exercise teaches
[?&]id=([^&#]*) ties the name to the start of a parameter, so uid=7 is skipped. The negated class stops the value at the next & or #. The star rather than a plus lets an empty value through.
A hint if you get stuck
Start with a class that holds the two characters a parameter can follow, [?&], then the literal id= and a negated class for the value.
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