For Loop beginner

[agoldav]

I'm just learning to code right now and Im experimenting with For Loops.
I tried this 2 options that I thought are the same but a get different results.

Anybody can tell me what the difference is?

a, b = 0, 1

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

a = 0
b = 1

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

[deanhystad]

This has nothing to do with for loops. The difference is how you do the assignment.

When you do "a, b = b, a + b", the assignment "a, b =" happens after "b, a + b" completes. The value of "a" does not change until after evaluating "a + b". It is like you wrote the program this way:

temp = a
a = b
b = temp + b

When you split this into multiple statements:

    a = b
    b = a + b

a is assigned a new value before calling "b = a + b"

Doing multiple assignments in one statement can be very useful. This is a common way to swap two values in Python.

a, b = b, a

In C you would need a temporary variable for this.

Output:
temp = a
a = b
b = temp

But you need to be careful when doing multiple assignments in one statement. Everything on the right side of the "=" is going to happen before assigning any values to the left side of the "=".

[agoldav]

Awesome, thanks for the help!!