CODEWITHSUNDEEP
c#.netregex
James
James

Reputation: 5642

search a string for another string that contains a special character

So right now I'm using this simple method to check a string for another string:

System.Text.RegularExpressions.Regex.IsMatch(toSearch, toVerifyisPresent, System.Text.RegularExpressions.RegexOptions.IgnoreCase)

Now, its working fine for the most part. But my biggest issue is that if I try to search for something like "areyou+present", if "areyou+present" IS there, it will still come back false. I'm thinking its because of the "+" in the string.

What can I do to work around this?

Upvotes: 0

Views: 420

Answers (4)

Jimmy
Jimmy

Reputation: 91472

Demo in IronPython:

>>> from System.Text.RegularExpressions import *
>>> Regex.IsMatch("This is a sentence containing 'areyou+present'", "areyou+present");
False
>>> Regex.IsMatch("This is a sentence containing 'areyou+present'", "areyou\\+present");
True
>>> Regex.IsMatch("This is a sentence containing 'areyou+present'", "areyou[+]present");
True
>>> Regex.IsMatch("This is a sentence containing 'areyou+present'", Regex.Escape("areyou+present"));
True

Upvotes: 1

diolemo
diolemo

Reputation: 2671

Based on the comment above by Oded.

toSearch.toLowerCase().Contains(toVerifyIsPresent.toLowerCase())

Converting both to lowercase will provide the same functionality as using IgnoreCase

Upvotes: 2

Serguei
Serguei

Reputation: 2958

In regular expressions + matches the previous group one or more times so the regex areyou+present matches:

areyoupresent
areyouupresent
areyouuuuuuuuuuuuuuuuuuuuuuuuuuupresent

etc...

Upvotes: 1

Abe Miessler
Abe Miessler

Reputation: 85056

You can escape special characters using a \. But as Oded points out if you are just checking to see if a string contains something you are better off using the String.Contains method.

Special Characters in regex:

http://www.regular-expressions.info/characters.html

String.Contains method:

http://msdn.microsoft.com/en-us/library/dy85x1sa.aspx

Upvotes: 3

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