Replace non-numeric with empty string

Question

Quick add on requirement in our project   A field in our DB to hold a phone number is set to only allow 10 characters   So  if I get passed   913 -444-5555  or anything else  is there a quick way to run a string through some kind of special replace function that I can pass it a set of characters to allow   Regex

User · Answer

for the best performance and lower memory consumption , try this:

using System;
using System.Diagnostics;
using System.Text;
using System.Text.RegularExpressions;

public class Program
{
    private static Regex digitsOnly = new Regex(@"[^\d]");

    public static void Main()
    {
        Console.WriteLine("Init...");

        string phone = "001-12-34-56-78-90";

        var sw = new Stopwatch();
        sw.Start();
        for (int i = 0; i < 1000000; i++)
        {
            DigitsOnly(phone);
        }
        sw.Stop();
        Console.WriteLine("Time: " + sw.ElapsedMilliseconds);

        var sw2 = new Stopwatch();
        sw2.Start();
        for (int i = 0; i < 1000000; i++)
        {
            DigitsOnlyRegex(phone);
        }
        sw2.Stop();
        Console.WriteLine("Time: " + sw2.ElapsedMilliseconds);

        Console.ReadLine();
    }

    public static string DigitsOnly(string phone, string replace = null)
    {
        if (replace == null) replace = "";
        if (phone == null) return null;
        var result = new StringBuilder(phone.Length);
        foreach (char c in phone)
            if (c >= '0' && c <= '9')
                result.Append(c);
            else
            {
                result.Append(replace);
            }
        return result.ToString();
    }

    public static string DigitsOnlyRegex(string phone)
    {
        return digitsOnly.Replace(phone, "");
    }
}

The result in my computer is:
Init...
Time: 307
Time: 2178

User · Answer

You don t need to use Regex   phone   new String phone Where c   gt  char IsDigit c   ToArray

User · Answer

You can do it easily with regex   string subject     913 -444-5555   string result   Regex Replace subject     0-9            result    9134445555

User · Answer

Using the Regex methods in  NET you should be able to match any non-numeric digit using  D  like so  phoneNumber    Regex Replace phoneNumber   quot   D quot   String Empty

User · Answer

You can do it easily with regex   string subject     913 -444-5555   string result   Regex Replace subject     0-9            result    9134445555

User · Answer

I m sure there s a more efficient way to do it  but I would probably do this   string getTenDigitNumber string input            StringBuilder sb   new StringBuilder        for int i - 0  i  lt  input Length  i                  int junk          if int TryParse input i   ref junk               sb Append input i              return sb ToString

User · Answer

Definitely regex   string CleanPhone string phone        Regex digitsOnly   new Regex      d            return digitsOnly Replace phone           or within a class to avoid re-creating the regex all the time   private static Regex digitsOnly   new Regex      d         public static string CleanPhone string phone        return digitsOnly Replace phone           Depending on your real-world inputs  you may want some additional logic there to do things like strip out leading 1 s  for long distance  or anything trailing an x or X  for extensions

User · Answer

try this  public static string cleanPhone string inVal                        char   newPhon   new char inVal Length               int i   0              foreach  char c in inVal                  if  c CompareTo  0    gt  0  amp  amp  c CompareTo  9    lt  0                      newPhon i      c              return newPhon ToString

User · Answer

How about an extension method that doesn t use regex   If you do stick to one of the Regex options at least use RegexOptions Compiled in the static variable   public static string ToDigitsOnly this string input        return new String input Where char IsDigit  ToArray         This builds on Usman Zafar s answer converted to a method group

User · Answer

Using the Regex methods in  NET you should be able to match any non-numeric digit using  D  like so  phoneNumber    Regex Replace phoneNumber   quot   D quot   String Empty

User · Answer

for the best performance and lower memory consumption , try this:

using System;
using System.Diagnostics;
using System.Text;
using System.Text.RegularExpressions;

public class Program
{
    private static Regex digitsOnly = new Regex(@"[^\d]");

    public static void Main()
    {
        Console.WriteLine("Init...");

        string phone = "001-12-34-56-78-90";

        var sw = new Stopwatch();
        sw.Start();
        for (int i = 0; i < 1000000; i++)
        {
            DigitsOnly(phone);
        }
        sw.Stop();
        Console.WriteLine("Time: " + sw.ElapsedMilliseconds);

        var sw2 = new Stopwatch();
        sw2.Start();
        for (int i = 0; i < 1000000; i++)
        {
            DigitsOnlyRegex(phone);
        }
        sw2.Stop();
        Console.WriteLine("Time: " + sw2.ElapsedMilliseconds);

        Console.ReadLine();
    }

    public static string DigitsOnly(string phone, string replace = null)
    {
        if (replace == null) replace = "";
        if (phone == null) return null;
        var result = new StringBuilder(phone.Length);
        foreach (char c in phone)
            if (c >= '0' && c <= '9')
                result.Append(c);
            else
            {
                result.Append(replace);
            }
        return result.ToString();
    }

    public static string DigitsOnlyRegex(string phone)
    {
        return digitsOnly.Replace(phone, "");
    }
}

The result in my computer is:
Init...
Time: 307
Time: 2178

User · Answer

I m sure there s a more efficient way to do it  but I would probably do this   string getTenDigitNumber string input            StringBuilder sb   new StringBuilder        for int i - 0  i  lt  input Length  i                  int junk          if int TryParse input i   ref junk               sb Append input i              return sb ToString

User · Answer

try this  public static string cleanPhone string inVal                        char   newPhon   new char inVal Length               int i   0              foreach  char c in inVal                  if  c CompareTo  0    gt  0  amp  amp  c CompareTo  9    lt  0                      newPhon i      c              return newPhon ToString

User · Answer

Using the Regex methods in  NET you should be able to match any non-numeric digit using  D  like so  phoneNumber    Regex Replace phoneNumber   quot   D quot   String Empty

User · Answer

You can do it easily with regex   string subject     913 -444-5555   string result   Regex Replace subject     0-9            result    9134445555

User · Answer

Definitely regex   string CleanPhone string phone        Regex digitsOnly   new Regex      d            return digitsOnly Replace phone           or within a class to avoid re-creating the regex all the time   private static Regex digitsOnly   new Regex      d         public static string CleanPhone string phone        return digitsOnly Replace phone           Depending on your real-world inputs  you may want some additional logic there to do things like strip out leading 1 s  for long distance  or anything trailing an x or X  for extensions

User · Answer

How about an extension method that doesn t use regex   If you do stick to one of the Regex options at least use RegexOptions Compiled in the static variable   public static string ToDigitsOnly this string input        return new String input Where char IsDigit  ToArray         This builds on Usman Zafar s answer converted to a method group

User · Answer

try this  public static string cleanPhone string inVal                        char   newPhon   new char inVal Length               int i   0              foreach  char c in inVal                  if  c CompareTo  0    gt  0  amp  amp  c CompareTo  9    lt  0                      newPhon i      c              return newPhon ToString

User · Answer

Here s the extension method way of doing it   public static class Extensions       public static string ToDigitsOnly this string input                Regex digitsOnly   new Regex      d             return digitsOnly Replace input

User · Answer

I m sure there s a more efficient way to do it  but I would probably do this   string getTenDigitNumber string input            StringBuilder sb   new StringBuilder        for int i - 0  i  lt  input Length  i                  int junk          if int TryParse input i   ref junk               sb Append input i              return sb ToString

User · Answer

I m sure there s a more efficient way to do it  but I would probably do this   string getTenDigitNumber string input            StringBuilder sb   new StringBuilder        for int i - 0  i  lt  input Length  i                  int junk          if int TryParse input i   ref junk               sb Append input i              return sb ToString

User · Answer

Definitely regex   string CleanPhone string phone        Regex digitsOnly   new Regex      d            return digitsOnly Replace phone           or within a class to avoid re-creating the regex all the time   private static Regex digitsOnly   new Regex      d         public static string CleanPhone string phone        return digitsOnly Replace phone           Depending on your real-world inputs  you may want some additional logic there to do things like strip out leading 1 s  for long distance  or anything trailing an x or X  for extensions

User · Answer

You can do it easily with regex   string subject     913 -444-5555   string result   Regex Replace subject     0-9            result    9134445555

User · Answer

You don t need to use Regex   phone   new String phone Where c   gt  char IsDigit c   ToArray

User · Answer

Here s the extension method way of doing it   public static class Extensions       public static string ToDigitsOnly this string input                Regex digitsOnly   new Regex      d             return digitsOnly Replace input

User · Answer

Using the Regex methods in  NET you should be able to match any non-numeric digit using  D  like so  phoneNumber    Regex Replace phoneNumber   quot   D quot   String Empty

User · Answer

try this  public static string cleanPhone string inVal                        char   newPhon   new char inVal Length               int i   0              foreach  char c in inVal                  if  c CompareTo  0    gt  0  amp  amp  c CompareTo  9    lt  0                      newPhon i      c              return newPhon ToString

User · Answer

Definitely regex   string CleanPhone string phone        Regex digitsOnly   new Regex      d            return digitsOnly Replace phone           or within a class to avoid re-creating the regex all the time   private static Regex digitsOnly   new Regex      d         public static string CleanPhone string phone        return digitsOnly Replace phone           Depending on your real-world inputs  you may want some additional logic there to do things like strip out leading 1 s  for long distance  or anything trailing an x or X  for extensions

[c#] Replace non-numeric with empty string

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