Ruby Bitwise Operators

Last update on August 19 2022 21:50:52 (UTC/GMT +8 hours)

Bitwise Operators

In Ruby, Bitwise operators allow to operate on the bitwise representation of their arguments.

What is a bit?

A bit (Binary digIT) is the basic unit of information stored in the computing system that exists in two possible states, represented as ON or OFF. In a computer system, the ON state considered as 1 and OFF state considered as 0. These states can be compared with two states of a flip-flop, two states of an electric switch etc. These two values 0 and 1 are called Binary digit and these digits are in a specific number system, that is BINARY number system which constructs upon the base of 2.

In decimal number system, a number construct upon the base of 10. Let us see how a decimal number can be constructed -

  231=(2 x 10²)+(3 x 10¹)+(1 x 10⁰)
      =200+30+1
      =231

The binary number system also follows the same concept. The only difference is the base is 2 instead of 10. Let us see how a binary number can be converted into a decimal number -

1011010=(1 x 2⁶)+(0 x 2⁵)+(1 x 2⁴)+(1 x 2³)+(0 x 2²)+(1 x 2¹)+(0 x 2⁰)
          =(1 x 64) +(0 x 32)+(1 x 16)+(1 x 8)+(0 x 4)+(1 x 2)+(0 x 1)
          =64+0+16+8+0+2+0
          =90

So, (1011010)₂= (90)₁₀ Byte

A byte is made up of a sequence of bits. A byte consists of eight bits. The maximum value of a byte is 255, so the place value of each bit is set.

Tabular representation of a byte

1 Byte ( 8 bits )
	8th	7th	6th	5th	4th	3rd	2nd	1st
Place value	128	64	32	16	8	4	2	1

Here is a Tabular representation of a byte shows how the maximum value of a byte is 255

1 Byte ( 8 bits )
Place Value	128	64	32	16	8	4	2	1
	1	1	1	1	1	1	1	1
	2⁷	2⁶	2⁵	2⁴	2³	2²	2¹	2⁰
	128	64	32	16	8	4	2	1	=	255

A decimal number 93 can be represent in binary form like bellow -

1 Byte ( 8 bits )
Place Value	128	64	32	16	8	4	2	1
	0	1	0	1	1	1	0	1
	2⁷	2⁶	2⁵	2⁴	2³	2²	2¹	2⁰
	0	64	0	16	8	4	0	1	=	93

Following Bitwise operators supported by Ruby language

Operator	Name	Example	Result
&	And	x &y	Bits that are set in both x and y are set.
\|	Or	x \| y	Bits that are set in either x or y are set.
^	Xor	x ^ y	Bits that are set in x or y but not both are set.
~	Not	~x	Bits that are set in x are not set, and vice versa.
<<	Shift left	x <<y	Shift the bits of x, y steps to the left.#
>>	Shift right	x >>y	Shift the bits of x, y steps to the right.*

# Each step means 'multiply by two'
* Each step means 'divide by two'

Example: Ruby bitwise operator

puts ("bitwise operators in Ruby")
a = 58      #  00111010
b = 34      #  00100010
puts ("Binary AND Operator")
puts (a&b)
puts ("Binary OR Operator")
puts (a|b)
puts ("Binary OR Operator")
puts (a^b)
puts ("Binary Ones Complement Operator")
puts (~a)
puts ("Binary Left Shift Operator")
puts (a<<4)
puts ("Binary Right Shift Operator")
puts (a>>4)

Output:

bitwise operators in Ruby
Binary AND Operator
34
Binary OR Operator
58
Binary OR Operator
24
Binary Ones Complement Operator
-59
Binary Left Shift Operator
928
Binary Right Shift Operator
3

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