Can regex be used to validate numbers OUTSIDE a range of specific numbers?

Question

I have referred to several SO webpages for the answer to my question, but I keep reading that regex should not be used for validating numbers which are less than or greater than a certain range. I want to ensure that a user enters numbers within the following ranges: 11--20 and 65-100. Anything less than 11 will not be allowed, anything between 21 and 64 will not be allowed and anything from 101 above will not be allowed. I realize I can write something like

                    if ($num <=10 and $num >= 21 and $num <=64 and $num >=101) {
                    $num = "";
                    $numErr = "Number must be within  specified ranges";
                    }

But what I really want is to use regex to preclude the range of numbers I do not want from being entered but I have not seen any satisfactory answers on SO. Can someone please help?

you might be able to write such regex, but will definitely be less readable than this. — fedorqui, Dec 31 '14 at 15:37
The regex approach will not scale to more varied ranges. For a more extreme example, look at http://stackoverflow.com/q/5365283/1233508 . — DCoder, Dec 31 '14 at 15:43

nu11p01n73R · Answer 1 · 2014-12-31T15:47:03.920

4

The regex would be less readable but like

/^(1[1-9]|20|6[5-9]|[7-9][0-9]|100)$/

Regex Demo

edited Dec 31 '14 at 15:47

answered Dec 31 '14 at 15:39

nu11p01n73R

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You need to surround the alternatives in (), if you want `^$` to work correctly: `^(..|.....|..)$`. – DCoder Dec 31 '14 at 15:42
@DCoder Yup. Edited in answer – nu11p01n73R Dec 31 '14 at 15:44
nu11p01n73R, I appreciate your help. Thanks. – Jason12 Dec 31 '14 at 16:12

Can regex be used to validate numbers OUTSIDE a range of specific numbers?

1 Answers1