Why?

Question

#I think those two(2) code are the same; right?
#but why the result goes different?

a = 0
b = 1

for i in range(10):
print(a)
a,b = b,a+b

#Line break
print("""

""")

c = 0
d = 1
for i in range(10):
print(c)
c = d
d = c+d

Answer 1

No it's not right 😉
In the first case, the tuple is unpacked

a = 0
b = 1
for i in range(10):
print(a)
# 1 0 1
a,b = b,a+b

#Line break
print("""

""")

c = 0
d = 1
for i in range(10):
print(c)
c = d
# 1 1
d = c+d

#Line break
print("""

""")

tuple = 0,1
for _ in range(10):
print(tuple[0])
tuple = tuple[1], tuple[0]+tuple[1]

Answer 2

In the first one the value of a in a+b is the one before the assignment. The assignments happen at the same time, I'm guessing. (the guess part is: I don't know if I'm allowed to call a, b = b, a+b a tuple, but it works like a tuple, the old values are used)

In the second one, c in c+d is the new c value.
The order of assignment is changed.

Answer 3

Solo
Korkunç el Gato
Rik Wittkopp
Thanks you all, best wish.

Answer 4

IbrahimCPS
a,b = b,a is a quick pythonic way to swap the values of 2 variables.

As you loop through the first code, the value growth of a is being inhibited because it keeps getting re-assigned the value of b

In your second code, the values of c & d are not swapping back & forth during the iterations, so c can grow at a steady exponential rate