char Array Regex.Match Regex.Replace String Constructor String Replace

`Regex.Replace`, spaces

Regex.Replace can act upon spaces. It can merge multiple spaces in a string to one space. We use a pattern to change multiple spaces to single spaces.

Metacharacters used

The characters "\s+" come in handy. This means "one or more whitespace characters—so we can replace 1 or more whitespace with just 1.

This program includes the System.Text.RegularExpressions namespace, which gives us easy access to Regex.Replace. In CollapseSpaces, we use the pattern "\s+" to indicate more than one whitespace.

Detail This will match newlines, carriage returns, spaces and tabs. We then replace this pattern with a single space.

Result You can see that the output values only have one space in between the words.

Note Sometimes, after processing text with other regular expressions and methods, multiple spaces will appear.

Tip CollapseSpaces() can solve that problem but results in even more complexity in the program.

using System;
using System.Text.RegularExpressions;

class Program
{
    static string CollapseSpaces(string value)
    {
        return Regex.Replace(value, @"\s+", " ");
    }

    static void Main()
    {
        string value = "Dot  Net  Perls";
        Console.WriteLine(CollapseSpaces(value));
        value = "Dot  Net\r\nPerls";
        Console.WriteLine(CollapseSpaces(value));
    }
}Dot Net Perls
Dot Net Perls

For performance, it would be better to replace it with a character-based implementation. It is possible to use a character array and then selectively write in characters, omitting unwanted ones.

Then You can use the string constructor to convert the character array back to a string.

Summary

We saw a whitespace-processing method that uses the Regex.Replace method. This method can process strings that are slightly invalid. It works well but increases overall complexity.

Regex.Replace, spaces

Metacharacters used

Summary

`Regex.Replace`, spaces