how to Search string for the exact word c#

Question

Hello Everybody,

I have string s= "Hello1 Hello2";

s.contains("Hello"); will return me true. but i want to see if the string contains the exact word "Hello" which it does not.

how can i do that?

Thanks,
Jan :)

Answer 1

U can use a regular expression like so:

bool contains = Regex.IsMatch("Hello1 Hello2", @"\bHello\b"); // yields false
bool contains = Regex.IsMatch("Hello1 Hello", @"\bHello\b"); // yields true

the \b is a word boundary check, and used like above it will be able to match whole words only.

Answer 2

I would suggest using Regex for this.  By appending the \b to either side of the text you're trying to match, you can find the "exact" match within the text.

Regex.IsMatch("Hello1 Hello2", "\bHello\b");

Something like this method below should work for you every time:

static bool ExactMatch(string input, string match)

{

    return Regex.IsMatch(input, string.Format(@"\b{0}\b", Regex.Escape(match)));

}

 

---

David Morton - http://blog.davemorton.net/

Answer 3

thanks guys :)

that was fast :)

Answer 4

Apparently the Regex does not consider the colon, so even if I write 'Hello:', true will still be returned. How can I fix that?

Answer 5

Im pretty sure you can test for "Hello " which will search for the space aswell.

Answer 6

Apparently the Regex does not consider the colon, so even if I write 'Hello:', true will still be returned. How can I fix that?

Well it's a matter of opinion if the colon is relevant or not, it depends upon the specific problem and your's is just one of a host of possible scenarios.

You'd need to define each case that you consider legal and then code for it, we cannot be expected to know that "Hello " is valid yet "Hello:" is not - unless you list this out.

If all you will accept is:

"Hello"

"Hello "

" Hello"

" Hello " 

then the code is trivial:

bool Contains(string Text, string Word)
{

if (Text == Word)
   return true;

if (Text.EndsWith(" " + Word) || Text.BeginsWith(Word + " "))
   return true;

if (Text.Contains(" " + Word + " "))
   return true;

}

Answer 7

Work as expected, Thanks