Answer to Question #80863 in Python for Abhi

Question

What is the value of pairs after the following assignment?
pairs=[(x,y) for x in range(4) for y in range(3) if (x+y)%3==0]

Answer 1

The value of pairs after execution of code: pairs=[(x,y) for x in range(4) for y in range(3) if (x+y)%3==0]
is [(0, 0), (1, 2), (2, 1), (3, 0)]

Explanation: for x in range(4) is outer loop and for y in range(3) is inner loop. The variable x is changed from 0 to 3 and variable y is changed from 0 to 2. The values are added to the list pairs only if this statement: if (x+y)%3==0 is True. The % is modulus operator that divides left operand (x+y) by right operand 3 and returns the remainder. The sum of (x+y) should be 0 or 3 to make the statement True.
The resulting variable pairs is a list of tuples.

The expression is equivalent to the following code:
pairs = []
for x in range(4):
for y in range(3):
if (x + y) % 3 == 0:
pairs += [(x, y)]