Multiple assignment and evaluation order in Python

Question

What is the difference between the following Python expressions:

# First:

x,y = y,x+y

# Second:

x = y
y = x+y

First gives diffe

Answer 1

a, b = 0, 1
while b < 10:
    print(b)
    a, b = b, a+b

Output

1
1
2
3
5
8

the variables a and b simultaneously get the new values 0 and 1, the same a, b = b, a+b, a and b are assigned simultaneously.