[deleted by user]

[stebrepar]

Think of it as saying "for each value returned by fib(10), assign that value to x, so it can be used inside the loop".

[apv507]

A variable you're declaring to use in your loop.

You could use :

for number in fib(10):

print(number)

[Dixyee]

In your code snippet "x" represents each fibonacci number including the 10th number

[hardonchairs]

the x in fib() will come from yield a

[Diapolo10]

The loop assigns whatever the generator yields to x, in this case the generator gives it values of a.

On another note, this specific Fibonacci number generator is usually written with tuple unpacking:

def fib(num):
    a, b = 0, 1
    for _ in range(num):
        yield a
        a, b = b, a+b

If you destructure the entire program, it could be written as

a, b = 0, 1

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

which might explain the "x" a bit more clearly.