I've been using the following Regex to extract a zip code from a bunch of text:
"\\d{5}\\-?[1-9]?[1-9]?[1-9]?[1-9]?"
My intention of making the last 4 [1-9] optional (using ? ) was to be able to extract both 5 digit zip codes and 5 digit zip codes with + 4 such as 11001-1010.
However, it only matches the first two digits of the last four numbers even though I put 4 digits at the end.
For example, in the zip code 11001-1010 it would match 11001-10.
Anyone know why?
Simple answer to question: For zip code 11001-1010 your regex would only match 11001-1 because the optional 4 digits after the - cannot be 0.
For the unstated question of how to fix that, it depends on whether you only want to match an optional +4, or you want to also match +3, +2, +1, and +0, like your expression would.
Matching Zip5 with optional +4, e.g. matching 11001-1010 and 11001:
"\\d{5}(?:-\\d{4})?"
Matching Zip5 with optional +N, e.g. matching 11001-1010, 11001-101, 11001-10, 11001-1, 11001-, and 11001:
"\\d{5}(?:-\\d{0,4})?"
Update
Now, if you want to make sure it doesn't match the 56789-1234 of 123456789-123456789 or abcd56789-1234qwerty, you can add a word-boundary check:
"\\b\\d{5}(?:-\\d{4})?\\b"
It's stopping at the first 0 in the suffix, "\d{5}\-?[1-9]?[1-9]?[1-9]?[1-9]?" So in your example, it only matches up to 11001-1 Does "\d{5}\-?[0-9]?[0-9]?[0-9]?[0-9]?" work ok? The other answers are probably cleaner, but that is the bug.
Looks ok per this
You can use \\d{5}\\-\\d{0,4} which allows you to match 0 to 4 digits after -.
EDIT
From the comment : But then the - won’t be optional.
For that you can use \\d{5}(\\-\\d{0,4})? to make group of - and digits after dash optional.
- won’t be optional.
"\\d{5}(?:\\-\\d{4})?".11001-1010your regex would only match11001-1because the optional 4 digits after the-cannot be0.x{0,4}is exactly the same asx?x?x?x?