How to get the count of only special character in a string using Regex?

Question

If my input string is ~!@#$%^&*()_+{}:\"<>?

How do I get the count of each special character using Regex? For example:

Regex.Match         


        

Answer 1

If you want to follow other approach then you can use.

string str =  "@123:*&^789'!@#$*()_+=";
            int count = 0;
            foreach (char c in str)
            {
                if (!char.IsLetterOrDigit(c.ToString(),0))
                {
                    count++;
                }
            }
            MessageBox.Show(count.ToString());

Answer 2

It's been a while and I needed a similar answer for handling password validation. Pretty much what VITA said, but here was my specific take for others needing it for the same thing:

var pwdSpecialCharacterCount = Regex.Matches(item, "[~!@#$%^&*()_+{}:\"<>?]").Count;
var pwdMinNumericalCharacters = Regex.Matches(item, "[0-9]").Count;
var pwdMinUpperCaseCharacters = Regex.Matches(item, "[A-Z]").Count;
var pwdMinLowerCaseCharacters = Regex.Matches(item, "[a-z]").Count;

Answer 3

Instead of thinking of every special characters and adding them up, do it the other way; count every letters/digits and subtract them from the count.

You can do that with a simple one-liner :

string input = "abc?&;3";
int numberOfSpecialCharacters = input.Length - input.Count(char.IsLetterOrDigit); //Gives 3

Which you can also change to

int numberOfSpecialCharacters = input.Count(c => !char.IsLetterOrDigit(c));

Answer 4

This should be the answer to your question:

Regex.Matches("Little?~ birds! like to@ sing##", "[~!@#$%^&*()_+{}:\"<>?]").Count

Count should return 6 matches, change the sentence to other variable or something else.

You can find more info about regex expressions here: http://www.zytrax.com/tech/web/regex.htm

Best Regards!

Answer 5

Regex is not the best way to do this. here is the Linq based solution

string chars = "~!@#$%^&*()_+{}:\"<>?";
foreach (var item in chars.Where(x=> !char.IsLetterOrDigit(x)).GroupBy(x => x))
{
    Console.WriteLine(string.Format("{0},{1}",item.Key,item.Count()));
}

I understand that you need to count each spl character count. Correct me If am mistaken.

Answer 6

The non-regex way (which sounds much easier) it to make a list of characters you want to check and use Linq to find the count of those characters.

string inputString = "asdf1!%jkl(!*";

List<char> charsToCheckFor = new List<char>() { '!', '@', '#', ..... };

int charCount = inputString.Count(x => charsToCheckFor.Contains(x));

I am making you write in all the characters you need to check for, because you need to figure out what you want.