How to make regex case insensitive?

Question

If I am matching a word in a regex 'Strict-Transport' how can I make it case insensitive? Is there any way other than putting the two character cases [Ss] for each character because it is not about the initials, but all the characters can come in any case?

I looked at previous posts but there are not like my case. This post for example shows how to make regex case insensitive when using list of characters []. But my case is a word in regex.

[That post](https://stackoverflow.com/questions/9655164/regex-ignore-case-sensitivity) shows all possibilities there are to help you. — Wiktor Stribiżew, May 11 '19 at 23:23

Kirill Polishchuk · Accepted Answer · 2019-05-11T23:16:39.530

24

You can use i modifier to make regex case-insensitive, e.g.:

(?i)ab

will match ab, Ab, aB and AB

edited May 11 '19 at 23:16

answered May 11 '19 at 23:13

Kirill Polishchuk

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Before every char? – user9371654 May 11 '19 at 23:14
@user9371654, no, it will set case-insensitivity for the whole expression. – Kirill Polishchuk May 11 '19 at 23:17
@user9371654 Same as [here](https://stackoverflow.com/a/9655203/3832970). – Wiktor Stribiżew May 11 '19 at 23:24
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I understand this is not the original question but sometimes including "on and off" in the answer is helpful instead of someone having to ask a separate question. if we wanted to turn it back on again for part of that same expression is there a way to disable case insensitivity? – John Aug 26 '20 at 23:21
@John, this setting applies to the whole regex – Kirill Polishchuk Aug 27 '20 at 03:35
Seems JS doesn't support it. It's sad. – Benyamin Limanto Mar 01 '21 at 07:16
Kotlin code below works. val format = "$1" var pattern = ("(?i)($word)").toRegex() var colorStr = str.replace(pattern, format) the format is ugly. no LF. – galian Nov 17 '21 at 08:10

How to make regex case insensitive?

1 Answers1