[SOLVED] How range works?????

Question

why :
print (range(20)==range (0,20))
is true

And

print (range (20)==range (20,0))
is false

Answer 1

This data type is characterized as: range(Start, Stop, Step). You specify the Start point, Stop (range ends *before* Stop, not including it) and skips every Step.

So range(3, 8, 2) will produce 3, 5, 7.
Now, range(20) is equal to range(0, 20, 1). But range(20, 0) is empty, as there are no numbers between 20 and 0, counting left-to-right.

You can count right-to-left though. In order to do that, your Step should be negative:
range(20, 0, -1) will produce 20, 19, 18, ..., 2, 1.

That won't be equal 0, 1, 2..., 19 (so range(20)), though.

Answer 2

@kuba, Luka
thank you both