How can I make a regular expression match upper and lower case?

Question

I don\'t really know much about regex at all, but if someone could help me change the following code to also allow for lowercase a-z, that would be great!

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Answer 1

If you want a regular expression to be case-insensitive, add a i modifier to the end of the regex. Like so:

/[A-Z]{3}([0-9]{1,4})?|[A-Z]{1,3}/i

Answer 2

/[A-Za-z]{3}([0-9]{1,4})?|[A-Za-z]{1,3}/

[] denotes a character class and A-Z is a allowed range and means ABCDEFGHIJKLMNOPQRSTUVWXYZ. You can extend this easy by adding a-z