function that returning index position of string after match found C#

Question

I have strings of 15 characters long..i am performing some pattern matching on it with the use of regular expression. i want to know the position of string where the isMatch() function returns true.

Is there is any function that return index position of a string

I want to perform some operation on that index.

Answer 1

Instead of using IsMatch, use the Matches method. This will return a MatchCollection, which contains a number of Match objects. These have a property Index.

Answer 2

Use Match instead of IsMatch:

    Match match = Regex.Match("abcde", "c");
    if (match.Success)
    {
        int index = match.Index;
        Console.WriteLine("Index of match: " + index);
    }

Output:

Index of match: 2

Answer 3

Regex.Match("abcd", "c").Index

2

Note# Should check the result of Match.success, because its return 0, and can confuse with Position 0, Please refer to Mark Byers Answer. Thanks.

Answer 4

Fot multiple matches you can use something like this

Regex rx = new Regex("as");
            foreach (Match match in rx.Matches("as as as as"))
            {
                int i = match.Index;
            }

Answer 5

Console.Writeline("Random String".IndexOf("om"));

This will output a 4

a -1 indicates no match

Answer 6

Rather than use IsMatch(), use Matches:

        const string stringToTest = "abcedfghijklghmnopqghrstuvwxyz";
        const string patternToMatch = "gh*";

        Regex regex = new Regex(patternToMatch, RegexOptions.Compiled);

        MatchCollection matches = regex.Matches(stringToTest); 

        foreach (Match match in matches )
        {
            Console.WriteLine(match.Index);
        }