Can i use regex to find the index of X?

Question

I have a big string, and want to find the first occurrence of X, X is \"numberXnumber\"... 3X3, or 4X9...

How could i do this in C#?

Answer 1

Yes, regex could do that for you

you could do ([0-9]+)X([0-9]+) If you know that the numbers are only single digit you could take [0-9]X[0-9]

Answer 2

For those who love extension methods:

public static int RegexIndexOf(this string str, string pattern)
{
    var m = Regex.Match(str, pattern);
    return m.Success ? m.Index : -1;
}

Answer 3

var index = new Regex("yourPattern").Match("X").Index;

Answer 4

http://www.regular-expressions.info/download/csharpregexdemo.zip

You can use this pattern:

\d([xX])\d

If I test

blaat3X3test

I get:

Match offset: 5 Match length: 3 Matched text: 3X3 Group 1 offset: 6 Group 1 length: 1 Group 1 text: X

Answer 5

Do you want the number, or the index of the number? You can get both of these, but you're probably going to want to take a look at System.Text.RegularExpressions.Regex

The actual pattern is going to be [0-9]x[0-9] if you want only single numbers (89x72 will only match 9x7), or [0-9]+x[0-9]+ to match the longest consecutive string of numbers in both directions.

Answer 6

this may help you

   string myText = "33x99 lorem ipsum  004x44";

    //the first matched group index
    int firstIndex =  Regex.Match(myText,"([0-9]+)(x)([0-9]+)").Index;

    //first matched "x" (group = 2) index 
    int firstXIndex =  Regex.Match(myText,"([0-9]+)(x)([0-9]+)").Groups[2].Index;