Regular expression from certain string

Question

I would like to know how to match a string with a regular expression for a certain length from a certain character or substring.

For example how do i match 5 characters back from the "tk" substring:

The string: "45gtyr eret dffg 45234tk ssdfr"

Should return: "45234".

Avinash Raj · Accepted Answer · 2015-03-12 12:40:58Z

3

Use a positive lookahead or capturing group.

.{5}(?=tk)

OR

(.{5})tk

answered Mar 12, 2015 at 12:40

Avinash Raj

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2 Comments

The first one does work great, the second one return "tk" as well as the 5 characters before it, But thank you very much! that helped me a lot :)

@RealGigex print the group index 1 in the second instead of index 0. Since you're new to stackoverflow, i suggest you to read this