CODEWITHSUNDEEP
c#
Snake Eyes
Snake Eyes

Reputation: 16754

Strange IndexOf of a string in c# which returns -1

I have a string which looks like:

var a = @"DISC INFO:

blablabla";

And I want to detect if DISC INFO exists in that string.

I did in simple way:

var index = a.IndexOf("disc info", StringComparison.OrdinalIgnoreCase);

It returns me -1 ...

Why ? I expected to find it

The entire C# code: https://dotnetfiddle.net/DAgxau

Upvotes: 3

Views: 121

Answers (3)

EpicKip
EpicKip

Reputation: 4033

There was a U+2002 : EN SPACE {nut} in between DISC and INFO.

I personally check this with notepad++, I'm not sure if you need any special settings to see the characters but this is how it looks:

enter image description here

So when using a normal space to match it won't work.

If you want to match unicode whitespace you can use Regex, credit to Marc Gravell.

Upvotes: 6

Marc Gravell
Marc Gravell

Reputation: 1062502

Ok then, how to detect that strange character with space in .net c# ?

Probably your best bet is to use a regex instead of a simple match; the \s token matches unicode whitespace, not just literal space character (ASCII 32):

var match = Regex.Match(a, @"disc\sinfo", RegexOptions.IgnoreCase);

(you can look at match.Success and match.Index, etc)

Note, however, that it is not quite true that everything that looks and smells like a space is categorized as a space in the unicode tables. Plus: the unicode tables evolve over time, so it depends which unicode version Regex on your runtime and operating system is using. Mostly it'll work, though.

Upvotes: 3

cdev
cdev

Reputation: 5341

Problem with your original string. enter image description here

Upvotes: 0

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