Question

I am not too good with regular expressions so this might be an obvious question.

I want my expression to match if a certain number of characters are found and fail if any extra characters are present. For example if I have a string that should have 4 digits the following should be true.

1234 – match
ab1234cd – does not match
012345 – does not match

What I have so far is \d{4} but my understanding is that this would just match any string that has 4 digits together in it anywhere. I want to match only if a string contains 4 digits and nothing else.

Any help would be appreciated. Thanks.

Answer 1

Use ^ and $ to mark the start/end of the string.