How can I delete all the non-numerical chars from a string and get the numerics only as a new string?

I have a long string witn many charaters like :

"8798dsfgsd98gs87£%"%001912.43.36."

How can I开发者_StackOverflow社区 delete all the non-numerical chars and get the numerics so that I can get:

"879898870019124336"

in C# ?

Thanks

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var text = "8798dsfgsd98gs87£%"%001912.43.36.";
var numText = new string( text.Where(c=>char.IsDigit(c)).ToArray() );

EDIT: If your goal is performance, use StringBuilder:

var text = "8798dsfgsd98gs87£%"%001912.43.36.";
var numText = new StringBuilder();
for(int i = 0; i < text.Length; i++) {
    char c = text[i];
    if ( char.IsDigit(c) ) {
        numText.Append(c);
    }
}

---

string text = "8798dsfgsd98gs87£%\"%001912.43.36.";
string digits = Regex.Replace(text, "[^0-9]", ""); // "879898870019124336"

---

Regex answer...

using System.Text.RegularExpressions;

private string justNumeric(string str)
{
    Regex rex = new Regex(@"[^\d]");
    return rex.Replace(str,"");
}

---

    string str = "8798dsfgsd98gs87£%%001912.43.36.";
    string result = string.Empty;
    for (int j = 0; j < str.Length; j++)
    {
        int i;
        try
        {
            i = Convert.ToInt16(str[j].ToString());
            result += i.ToString();
        }
        catch { }
    }

Try this way.....

---

Another regex answer;

string str = "8798dsfgsd98gs87£%%001912.43.36.";
string justNumbers = new Regex(@"\D").Replace(str,"");