BitSet class methods in Java with Examples

BitSet class methods in Java with Examples | Set 3

Last Updated : 16 Aug, 2018

                       BitSet class methods in Set 3.
               /      /      |       |     |       \      \
            and  notand    flip  isEmpty  equal   get   intersect

BitSet class methods in Java with Examples | Set 2

BitSet class methods are explained as follows :

and / notand : java.util.BitSet.and() and java.util.BitSet.notand() method is a java.util.Bitset class method.
.and() method performs logical AND operation of bit set(target) with the bit set passed as an argument. This will return a bit (set) if and only if both the bits that are being operated are true.
.notand() method – All those bits having it’s corresponding bit – Set are cleared using this method
```
Syntax:
public void and(BitSet bitset)
           or
public void andNot(BitSet bitste)
Parameters:
bitset - set to perform the operation
```

equal : java.util.BitSet.equal() method plays its role in comparing two bitset. It does so by comparing an object with other.

Syntax:
public boolean equals(Object o)
Parameters: 
o - the object to compare with
Overrides: equals in class Object
Return: if object are same then true; otherwise false

get() : java.util.BitSet.get() method creates a new BitSet with elements from the given Bitset having positions from from_Index (inclusive) to_Index(exclusive).

Syntax:
public BitSet get(int from_Index,  int to_Index)
Parameters:
from_Index - index of the first bit of given BitSet to include
to_Index - index after the last bit of the BitSet to include
Throws:
IndexOutOfBoundsException - if from_Index is negative, or to_Index is negative,
                            or from_Index is larger than to_Index

Java code explaining the use of and(), notand(), equal(), get() methods.

// Java program explaining BitSet class methods
// and(), notand(), equal(), get()
import java.util.*;
public class GFG
{
    public static void main(String[] args)
    {
        BitSet bs1 = new BitSet();
        BitSet bs2 = new BitSet();
  
        // assign values to bs1 using set()
        bs1.set(7);
        bs1.set(1);
        bs1.set(2);
        bs1.set(4);
        bs1.set(3);
        bs1.set(6);
  
        // assign values to bs2
        bs2.set(4);
        bs2.set(6);
        bs2.set(3);
        bs2.set(9);
        bs2.set(2);
  
        // Printing the Bitsets
        System.out.println("bs1         : " + bs1);
        System.out.println("bs2         : " + bs2);
  
        // use of get() to get index 3 to 6 of bs1
        System.out.println("\nUse of get() on bs1 : "
                                      + bs1.get(1,4));
  
        // use of get() to get index 1 to 4 of bs2
        System.out.println("Use of get() on bs2 : "
                                    + bs2.get(1,4));
  
        // perform not operation in b/w the sets
        bs1.andNot(bs2);
        System.out.println("\nNot b/w bs1 and bs2 : " + bs1);
  
        // perform and operation between two bitsets
        bs1.and(bs2);
        System.out.println("And b/w bs1 and bs2 : "  + bs1);
  
        // equal() method to compare the bs1 and bs2
        if (bs1.equals(bs2))
            System.out.println("\nUsing equal method : Equal");
        else
            System.out.println("\nUsing equal method : Not Equal");
    }
}

Output:

bs1         : {1, 2, 3, 4, 6, 7}
bs2         : {2, 3, 4, 6, 9}

Use of get() on bs1 : {0, 1, 2}
Use of get() on bs2 : {1, 2}

Not b/w bs1 and bs2 : {1, 7}
And b/w bs1 and bs2 : {}

Using equal method : Not Equal

flip() : java.util.BitSet.flip(from_Index, to_Index) method sets each bit from the given from_Index (inclusive) to the specified to_Index (exclusive) to current value’s compliment.

Syntax:
public void flip(int from_Index, int to_Index)
Parameters:
from_Index - index of the first bit of the given BitSet to flip
to_Index - index after the last bit of the given BitSet to flip
Throws:
IndexOutOfBoundsException - if from_Index is negative, or to_Index is negative, 
                            or from_Index is larger than to_Index

intersect() : java.util.BitSet.intersect() method returns true if both the bits in target BitSet and the given BitSet are set.

Syntax:
public boolean intersects(BitSet set)
Parameters:
set - BitSet to intersect with
Returns: true if the given BitSet intersects the target BitSet

isEmpty() : java.util.BitSet.isEmpty() method whether there is any bit, that is set to true or not in the given Bitset.

Syntax:
public boolean isEmpty()
Return: boolean indicating whether the given BitSet is empty

Java code explaining the use of intersect(), isEmpty(), flip() methods.

// Java program explaining BitSet class methods
// intersect(), isEmpty(), flip() methods
import java.util.*;
public class NewClass
{
    public static void main(String[] args)
    {
        BitSet bs1 = new BitSet();
        BitSet bs2 = new BitSet();
  
        // assign values to bs1 using set()
        bs1.set(7);
        bs1.set(1);
        bs1.set(2);
        bs1.set(4);
        bs1.set(3);
        bs1.set(6);
  
        // assign values to bs2
        bs2.set(4);
        bs2.set(6);
        bs2.set(3);
        bs2.set(9);
        bs2.set(2);
  
        // Printing the Bitsets
        System.out.println("bs1      : " + bs1);
        System.out.println("bs2      : " + bs2);
        System.out.println("");
  
  
        // use of intersect() to check if the bitsets
        // intersects
        System.out.println("Using intersect() : "
                     + bs2.intersects(bs1));
  
        // use of flip() from_index - 1 to_index - 5
        bs1.flip(1,5);
        System.out.println("\nbs1 using flip : " + bs1);
  
        // use of flip() from_index - 2 to_index - 4
        bs2.flip(2,4);
        System.out.println("bs2 using flip : " + bs2);
        System.out.println("");
  
  
        // use of isEmpty() to check if bitsets are empty
        System.out.println("Use of isEmpty() : "
                            + bs1.isEmpty());
        System.out.println("Use of isEmpty() : "
                             + bs2.isEmpty());
    }
}

Output:

bs1      : {1, 2, 3, 4, 6, 7}
bs2      : {2, 3, 4, 6, 9}

Using intersect() : true

bs1 using flip : {6, 7}
bs2 using flip : {4, 6, 9}

Use of isEmpty() : false
Use of isEmpty() : false

References :
https://docs.oracle.com/javase/7/docs/api/java/util/BitSet.html

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