Regex- Extract a text that is between 1 and 8 chars and does not contain more than 2 letters ([A-Za-z])

Question

I would like to extract a text using Regex that is between 1 and 8 chars and does not contain more than 2 letters ([A-Za-z]).

For example:

Valid: "12A-32B" from the text "Register:12A-32B Index:A"
Invalid: "12 Index" from the text "Register:12 Index:A"

In this example, the extracted text should have the text "Register" as a boundary.

I tried using positive/negative lookahead but to no avail.

Thank you.

From `Register:12A-32B Index:A` - why shouldn't e.g. `er:12`, or `32B I`? And why not `r:12 I` from the second? I assume it has to do with word boundaries (**but that's not stated in the question**). Going on: `:12 ` in the second? `:A` from the same? Why not those? — SamWhan, Jun 12 '17 at 14:03

Tim Biegeleisen · Accepted Answer · 2017-06-12T14:06:13.380

2

Try this regex:

^(?!.*[A-Za-z].*[A-Za-z].*[A-Za-z])[A-Za-z0-9-]{1,8}$

This will match any string containing at most 8 numbers or letters, with a maximum of 2 letters appearing in the string.

You may need an additional step to extract the text inside your original text. You could try using this regex:

Register:(.*) Index

We could try using a single regex for everything, but it would be complicated. And it might be easier to just use two steps from your app layer.

Demo

edited Jun 12 '17 at 14:06

answered Jun 12 '17 at 13:24

Tim Biegeleisen

@ClasG I updated my answer to allow hyphen in addition to letters and numbers (aside from what is forbidden from the assertion). – Tim Biegeleisen Jun 12 '17 at 14:06
Thank you for helping me – Daniel Jun 13 '17 at 05:37
@Daniel Not a problem :-) – Tim Biegeleisen Jun 13 '17 at 05:39

score 0 · Answer 2 · answered Jun 13 '17 at 10:53

0

I found the solution

answered Jun 13 '17 at 10:53

Daniel