BitArray.Or Method (BitArray)


Performs the bitwise OR operation between the elements of the current BitArray object and the corresponding elements in the specified array. The current BitArray object will be modified to store the result of the bitwise OR operation.

Namespace:   System.Collections
Assembly:  mscorlib (in mscorlib.dll)

public BitArray Or(
	BitArray value


Type: System.Collections.BitArray

The array with which to perform the bitwise OR operation.

Return Value

Type: System.Collections.BitArray

An array containing the result of the bitwise OR operation, which is a reference to the current BitArray object.

Exception Condition

value is null.


value and the current BitArray do not have the same number of elements.

The bitwise OR operation returns true if one or both operands are true, and returns false if both operands are false.

This method is an O(n) operation, where n is Count.

The following code example shows how to perform the OR operation between two BitArray objects.

using System;
using System.Collections;
public class SamplesBitArray  {

   public static void Main()  {

      // Creates and initializes two BitArrays of the same size.
      BitArray myBA1 = new BitArray( 4 );
      BitArray myBA2 = new BitArray( 4 );
      myBA1[0] = myBA1[1] = false;
      myBA1[2] = myBA1[3] = true;
      myBA2[0] = myBA2[2] = false;
      myBA2[1] = myBA2[3] = true;

      // Performs a bitwise OR operation between BitArray instances of the same size.
      Console.WriteLine( "Initial values" );
      Console.Write( "myBA1:" );
      PrintValues( myBA1, 8 );
      Console.Write( "myBA2:" );
      PrintValues( myBA2, 8 );

      Console.WriteLine( "Result" );
      Console.Write( "OR:" );
      PrintValues( myBA1.Or( myBA2 ), 8 );

      Console.WriteLine( "After OR" );
      Console.Write( "myBA1:" );
      PrintValues( myBA1, 8 );
      Console.Write( "myBA2:" );
      PrintValues( myBA2, 8 );

      // Performing OR between BitArray instances of different sizes returns an exception.
      try  {
         BitArray myBA3 = new BitArray( 8 );
         myBA3[0] = myBA3[1] = myBA3[2] = myBA3[3] = false;
         myBA3[4] = myBA3[5] = myBA3[6] = myBA3[7] = true;
         myBA1.Or( myBA3 );
      } catch ( Exception myException )  {
         Console.WriteLine("Exception: " + myException.ToString());

   public static void PrintValues( IEnumerable myList, int myWidth )  {
      int i = myWidth;
      foreach ( Object obj in myList ) {
         if ( i <= 0 )  {
            i = myWidth;
         Console.Write( "{0,8}", obj );


This code produces the following output.

Initial values
myBA1:   False   False    True    True
myBA2:   False    True   False    True

OR:   False    True    True    True

After OR
myBA1:   False    True    True    True
myBA2:   False    True   False    True

Exception: System.ArgumentException: Array lengths must be the same.
   at System.Collections.BitArray.Or(BitArray value)
   at SamplesBitArray.Main()

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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