Regex on a substring

Question

Is it possible to create a regex that only evaluates the first n number of characters in a string?

For example, given the strings:

Line 1: The quick brown fox jumped over the lazy dog.
Line 2: There was another fox that was not so quick.

I need a regex that only searches for the word quick within the first 15 characters. Such that line1 would match, but line2 would not match.

I'm interested in a single regex without combining with other commands, such as cut -c1-15, or something similar.

I understand that regex 'lookarounds' might be a possible solution, but can't seem to find anything that allows referencing position from the start of the input string.

Scott Weaver · Accepted Answer · 2018-12-13 19:49:27Z

2

You can quantify (with a range) a "dot anything" wildcard token and anchor the pattern to start of string to achieve this:

^.{1,15}quick

regex 101 demo

answered Dec 13, 2018 at 19:49

Scott Weaver

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4 Comments

Usman Over a year ago

but the regex fail when quick place start of the string.

Scott Weaver Over a year ago

yeah it would be {0,14} technically

BrentR Over a year ago

I made your answer the accepted one. We can substitute the value to be whatever is required. Thank you.

BrentR Over a year ago

One more followup...this solution technically provides a match no further away from the front than n characters. Not within the first n characters. But the numbers can be adjusted to achieve the desired effect.

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