C# | Trim() Method

C# Trim() is a string method. This method is used to removes all leading and trailing white-space characters from the current String object. This method can be overloaded by passing arguments to it.

Syntax:

public string Trim()  
or
public string Trim (params char[] trimChars)

Explanation : First method will not take any parameter and the second method will take an array of Unicode characters or null as a parameter. Null is because of params keyword. The type of Trim() method is System.String.

Note: If no parameter is pass in public string Trim() then Null , TAB, Carriage Return and White Space will automatically remove if they are present in current string object. And If any parameter will pass into the Trim() method then only specified character(which passed as arguments in Trim() method) will be removed from the current string object. Null, TAB, Carriage Return, and White Space will not remove automatically if they are not specified in the arguments list.

Below are the programs to demonstrate the above method :

• Example 1: Program to demonstrate the public string Trim() method. The Trim method removes all leading and trailing white-space characters from the current string object. Each leading and trailing trim operation stops when a non-white-space character is encountered. For example, If current string is ” abc xyz ” and then Trim method returns “abc xyz”.

  // C# program to illustrate the
  // method without any parameters
  using System;
  
  class GFG {
  
      // Main Method
      public static void Main()
      {
          string s1 = " GFG";
          string s2 = " GFG ";
          string s3 = "GFG ";
  
          // Before Trim method call
          Console.WriteLine("Before:");
          Console.WriteLine(s1);
          Console.WriteLine(s2);
          Console.WriteLine(s3);
  
          Console.WriteLine("");
  
          // After Trim method call
          Console.WriteLine("After:");
          Console.WriteLine(s1.Trim());
          Console.WriteLine(s2.Trim());
          Console.WriteLine(s3.Trim());
      }
  }
  Output:

  Before:
   GFG
   GFG 
  GFG 
  
  After:
  GFG
  GFG
  GFG
  

• Example 2: Program to demonstrate the public string Trim (params char[] trimChars) method. The Trim method removes from the current string all leading and trailing characters which are present in the parameter list. Each leading and trailing trim operation stops when a character which is not in trimChars encountered. For example, current string is “123abc456xyz789” and trimChars contains the digits from “1 to 9”, then Trim method returns “abc456xyz”.

  // C# program to illustrate the
  // method with parameters
  using System;
  
  class GFG {
  
      // Main Method
      public static void Main()
      {
  
          // declare char[] array and
          // initialize character 0 to 9
          char[] charsToTrim1 = {'1', '2', '3', '4', '5',
                                 '6', '7', '8', '9'};
  
          string s1 = "123abc456xyz789";
          Console.WriteLine("Before:" + s1);
          Console.WriteLine("After:" + s1.Trim(charsToTrim1));
  
          Console.WriteLine("");
  
          char[] charsToTrim2 = { '*', '1', 'c' };
          string s2 = "*123xyz********c******c";
          Console.WriteLine("Before:" + s2);
          Console.WriteLine("After:" + s2.Trim(charsToTrim2));
  
          Console.WriteLine("");
  
          char[] charsToTrim3 = { 'G', 'e', 'k', 's' };
          string s3 = "GeeksForGeeks";
          Console.WriteLine("Before:" + s3);
          Console.WriteLine("After:" + s3.Trim(charsToTrim3));
  
          Console.WriteLine("");
  
          string s4 = "     Geeks0000";
          Console.WriteLine("Before:" + s4);
          Console.WriteLine("After:" + s4.Trim('0'));
      }
  }
  Output:

  Before:123abc456xyz789
  After:abc456xyz
  
  Before:*123xyz********c******c
  After:23xyz
  
  Before:GeeksForGeeks
  After:For
  
  Before:     Geeks0000
  After:     Geeks
  

Important Points About Trim() Method:

• If the Trim method removes any characters from the current instance, then this method does not modify the value of the current instance. Instead, it returns a new string in which all leading and trailing whitespace characters of the current instance will be removed out.
• If the current string equals Empty or all the characters in the current instance consist of white-space characters, the method returns Empty.

Reference: https://msdn.microsoft.com/en-us/library/system.string.trim