正则表达式。替换不适用于分隔符

Question

I just want to replace with String.Empty if any Separators found in a given string.

class Program
{
    private const string Separators = "-(). ";
    static void Main(string[] args)
    {
        var number = Format("88 88-88)8.8(88");
    }

    public static string Format(string number)
    {
        return Regex.Replace(number, Separators, string.Empty);
    }
}

Expected is : 8888888888 But was 88 88-88)8.8(88 . Did i miss something here.

Edit : if use

Separators.ToCharArray().ToList().ForEach(c => { number = number.Replace(c.ToString(), string.Empty);});

it works. But it could be better if i achieve with Regex.Replace .

Answer 1

When you are using a regular expression some characters have certain meanings. A dot means "any character", a dash means a range as in 0-9. I've escaped the characters and put them in a character set [] which means "any one in this set". I also renamed your Separators variable to better reflect what it is now.

Try this instead:

class Program
{
    private const string SeparatorsRegex = @"[\-()\. ]";
    static void Main(string[] args)
    {
        var number = Format("88 88-88)8.8(88");
    }

    public static string Format(string number)
    {
        return Regex.Replace(number, SeparatorsRegex, string.Empty);
    }
}

Tested it in Expresso and this worked as expected. Its a great tool for regex dev:

• http://www.ultrapico.com/Expresso.htm

(Ignore the terrible site design, it is a good util honest :P )

A further note, is that if you just want to strip everything that isnt a number then you could actually use this:

class Program
{
    private const string StripNonNumbersRegex = @"[^\d]";
    static void Main(string[] args)
    {
        var number = Format("88 88-88)8.8(88");
    }

    public static string Format(string number)
    {
        return Regex.Replace(number, StripNonNumbersRegex, string.Empty);
    }
}

Answer 2

Regex.Replace() works on patterns, not separators. You are confusing it with String.Replace() .

String.Replace(source, "-", string.empty) will work, but you will need to run this once per character. Regex.Replace(source, pattern, string.empty) will work better, but you need to use a RegEx pattern , not simple list the characters.