Extract numbers from string to create digit only string [duplicate]

Answer 1

You could use LINQ. The code below filters the string into an IEnumerable with only digits and then converts it to a char[]. The string constructor can then convert the char[] into a string:

string a = "557222]]>";
string b = "5100870<br>";

a = new string(a.Where(x => char.IsDigit(x)).ToArray());
b = new string(b.Where(x => char.IsDigit(x)).ToArray());

Answer 2

Not familiar enough with .NET for exact code. Nonetheless, two approaches would be:

• Cast it as an integer. If the non-digit characters are at the end (i.e. 21389abc), this is the easiest.
• If you have intermixed non-digit characters (i.e. 1231a23v) and want to keep every digit, use the regex [^\d] to replace non-digit characters.

Answer 3

Here's the version that worked for my case

    public static string ExtractNumbers(this string source)
    {
        if (String.IsNullOrWhiteSpace(source))
            return string.Empty;
        var number = Regex.Match(source, @"\d+");
        if (number != null)
            return number.Value;
        else
            return string.Empty;
    }

Answer 4

Try this

string number = Regex.Match("12345<br>", @"\d+").Value;

This will return the first group of digits. Example: for the input "a 123 b 456 c" it will return "123".

Answer 5

You can use a simple regular expression:

var numericPart = Regex.Match( a, "\\d+" ).Value;

If you need it to be an actual numeric value, you can then use int.Parse or int.TryParse.

Answer 6

Try this oneliner:

Regex.Replace(str, "[^0-9 _]", "");