Strange if statement

Question

I found this strange if-statement in somebody else’s code:

if variable & 1 == 0:

I don\'t understand it. It should have two

Answer 1

Your only concern is probably the operator &. It is a bitwise and which takes the binary format of the two operands and perform "logic and" on each pair of bits.

For your example, consider the following:

variable = 2  #0b0010
if variable & 1 == 0:
    print "condition satisfied" # satisfied, 0b0010 & 0b0001 = 0

variable = 5  #0b0101
if variable & 1 == 0:
    print "condition satisfied" # not satisfied, 0b0101 & 0b0001 = 1

Note:

variable = 6  #0b0110
if variable & 2 == 0:
    print "condition satisfied" # not satisfied, 0b0110 & 0b0010 = 2 (0b0010)