String compare C# - whole word match

Question

I have two strings:

string1  = "theater is small"; 
string2 =  "The small thing in the world";

I need to check weather the string "the" is present in the strings or not.
I can use the contains function, but can it do a whole word match? i.e it should not match with "theater" of string1!

Konrad Rudolph · Answer 1 · 2012-06-14T15:58:01.553

71

The simplest solution is to use regular expressions and the word boundary delimiter \b:

bool result = Regex.IsMatch(text, "\\bthe\\b");

or, if you want to find mismatching capitalisation,

bool result = Regex.IsMatch(text, "\\bthe\\b", RegexOptions.IgnoreCase);

(using System.Text.RegularExpressons.)

Alternatively, you can split your text into individual words and search the resulting array. However, this isn’t always trivial because it’s not enough to split on white spaces; this would ignore all punctuation and yield wrong results. A solution is to once again use regular expressions, namely Regex.Split.

edited Jun 14 '12 at 15:58

answered Oct 11 '10 at 08:36

Konrad Rudolph

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4

You might also want to specify RegexOptions.IgnoreCase – Paolo Tedesco Oct 11 '10 at 08:40
1

Your parameters are backwards! The input comes first, then the pattern to match. – Dan Bailiff Jun 14 '12 at 14:30
it is passing "The small thing in the-world" also but my requirement is it should be return false. – chetanya gehlot Jul 15 '16 at 09:24
There's a typo in the answer for the using directive-namespace. It's `System.Text.RegularExpressions` – Alex P. Apr 16 '22 at 08:55

score 14 · Answer 2 · answered Oct 11 '10 at 08:37

Use the method Regex.IsMatch using \bthe\b, \b represents a word boundary delimiter.

// false
bool string1Matched = Regex.IsMatch(string1, @"\bthe\b", RegexOptions.IgnoreCase); 

// true
bool string2Matched = Regex.IsMatch(string2, @"\bthe\b", RegexOptions.IgnoreCase);

score 6 · Answer 3 · answered Oct 11 '10 at 09:25

6

str.Split().Contains(word);

or

char[] separators = { '\n', ',', '.', ' ' };    // add your own
str.Split(separators).Contains(word);

answered Oct 11 '10 at 09:25

Grozz

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score 0 · Answer 4 · answered Sep 06 '18 at 16:17

Using the answers here i made this extension method that finds multiple words in a text, returns the amount of words found, and ignores case matching.

public static int Search(this String text, params string[] pValores)
{
    int _ret = 0;
    try
    {
        var Palabras = text.Split(new char[] { ' ', '.', '?', ',', '!', '-', '(', ')', '"', '\''  }, 
            StringSplitOptions.RemoveEmptyEntries);

        foreach (string word in Palabras)
        {
            foreach (string palabra in pValores)
            {
                if (Regex.IsMatch(word, string.Format(@"\b{0}\b", palabra), RegexOptions.IgnoreCase))
                {
                    _ret++;
                }
            }
        }               
    }
    catch { }
    return _ret;
}

Usage:

string Text = @"'Oh, you can't help that,' (said the Cat) 'we're all mad here. I'm MAD. ""You"" are mad.'";
int matches = Text.Search("cat", "mad"); //<- Returns 4

It's not perfect but it works.

score -1 · Answer 5 · answered Jul 22 '14 at 12:18

-1

you can if you add the space in the word that you examine

answered Jul 22 '14 at 12:18

Amjad Abdelrahman

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This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. – Black Sheep Jul 22 '14 at 12:39
that will often work but not if, for example, you search the string for "the " and the string *ends* with "the" as in: "this won't find the" – mtijn Jul 22 '14 at 12:50
@aldanux sorry but this *is* an answer to the question, just not a very good one and also a very late one... – mtijn Jul 22 '14 at 12:54

score -2 · Answer 6 · answered Oct 11 '10 at 08:36

-2

You could use a regular expression instead. That way you can specify that you only want space or end of line in the end.

answered Oct 11 '10 at 08:36

Tomas Jansson

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String compare C# - whole word match

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