CODEWITHSUNDEEP
c#regex
core
core

Reputation: 33087

C# RegEx: Ignore case... in pattern?

I'm using System.Text.RegularExpressions.Regex.IsMatch(testString, regexPattern) to do some searches in strings.

Is there a way to specify in the regexPattern string that the pattern should ignore case? (I.e. without using Regex.IsMatch(testString, regexPattern, RegexOptions.IgnoreCase))

Upvotes: 88

Views: 60378

Answers (2)

Tore Aurstad
Tore Aurstad

Reputation: 3826

You can find the available inline options here:

https://learn.microsoft.com/en-us/dotnet/standard/base-types/regular-expression-options

At the top table, the column inline character shows the recognized option. You either wrap the part of the regex where the regex should be applied inside. In general you use:

(?options) ... (?-options). You can combine multiple inline options here, options can be for example 'ix' where 'x' is IgnorePatternWhitespace .

For example: (?i)Tim(?-i) corey

Matches :

"Tim corey" but not "Tim Corey" since only Tim here is case insensitive. "tim corey" also matches. (I am following a Regex video tutorial by Tim Corey right now and he uses his name all the time in examples, so I am also using his name here).

Upvotes: 0

stevemegson
stevemegson

Reputation: 12103

(?i) within the pattern begins case-insensitive matching, (?-i) ends it. That is,

(?i)foo(?-i)bar

matches FOObar, fOobar and foobar but not fooBAR.

EDIT: I should have said (?-i) starts case-sensitive matching - if you want the whole pattern to be case-insensitive then you don't need to "end" the (?i).

Upvotes: 169

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