Regular expression for positive integers, 2 to 4 digits but no 00, 000 or 0000

Question

I would like to use regular expression to match only positive integers at least 2 but no more than 4 digits. I know that I can do that with this regex: ^\d{2,4}$

Now, I want to exclude 00, 000, 0000 and also leading zeros such as 02, 003, 0001. Any suggestion?

Thanks in advance.

No i dont want leading zeros. Thank you @Shar1er80 for the comment. — Kiki, Aug 08 '15 at 20:09
`At least 2 but not more than 4 digits` -> I'm voting to reopen this question as not a duplicate. — Maximillian Laumeister, Aug 08 '15 at 23:30

Wiktor Stribiżew · Answer 1 · 2015-08-08T20:19:40.033

2

You can impose restrictions using a lookahead anchored at the beginning:

^(?!0+)\d{2,4}$

See demo

The negative lookahead (?!0+) checks at the beginning of a string (as it is located right after the ^ anchor) if there are any 1 or more zeros (with 0+).

edited Aug 08 '15 at 20:19

answered Aug 08 '15 at 20:07

Wiktor Stribiżew

607,720
39
448
563

Thank you very much but this allows leading zeros. – Kiki Aug 08 '15 at 20:16
Now it does not, I removed the end of line anchor. – Wiktor Stribiżew Aug 08 '15 at 20:19
Sorry you are right. Thank you very much. – Kiki Aug 08 '15 at 20:22

score 1 · Accepted Answer · answered Aug 08 '15 at 20:04

1

Maybe something like:

^[1-9]\d{1,3}$

The first part, [1-9] makes sure the first digit is not a 0, after that, any digits can follow, up to a maximum of 4 in total.

answered Aug 08 '15 at 20:04

Gato

671
5
15

Thank you very much this seems to work perfectly. – Kiki Aug 08 '15 at 20:13

Regular expression for positive integers, 2 to 4 digits but no 00, 000 or 0000

2 Answers2