Bitwise Operators in Swift

It's not frequently used in a regular job but loved by interviewers. Remember to to represent a bit add 0b to a number. For example 0b1 would be one bit that is equal 1 in decimal value.

Bitwise AND

The AND operation takes two bits and returns 1 if both bits are 1. Otherwise, it returns 0.

0b11 & 0b10 // → 2
0b1 & 0b0 // → 0
0b0 & 0b1 // → 0
0b0 & 0b0 // → 0
0b1 & 0b1 // → 1

Bitwise OR

The OR operation takes two bits and returns 1 if either of the bits are 1. Otherwise, it returns 0.

0b11 | 0b10 // → 3
0b1 | 0b0 // → 1
0b0 | 0b1 // → 1
0b0 | 0b0 // → 0

Bitwise XOR

The XOR operation (or exclusive or) takes two bits and returns 1 if exactly one of the bits is 1. Otherwise, it returns 0.

0b1 ^ 0b1 // →  0
0b1 ^ 0b0 // →  1
0b0 ^ 0b1 // →  1
0b0 ^ 0b0 // →  0

Bitwise Not

The NOT bitwise operation takes one set of bits, and for each bit returns 0 if the bit is 1, and 1 if the bit is 0.
More reading: https://en.wikipedia.org/wiki/Two's_complement

~0b0 // →  -1
~0b1 // →  -2

Bit Shifting

A bit shift moves each digit in a number's binary representation left or right. The last bit in the direction of the shift is lost, and a 00 bit is inserted on the other end.

0b0010 << 1 // →  0100
0b1011 >> 1 // →  0101

Bit shifts take number of times to shift as the right argument:
left shift divided by 2 to the power number of shifts, right shift divides by 2 to the power of number of shifts

0b1010110 << 2  //→  1011000 =0 344
0b1011010 >> 3  //→  0001011```