Need help in python slicing

Question

X = [1, 2, 3, 4, 5, 6]
print(x[::-2])

The output should be = [5, 3, 1]
But the real output is = [6, 4, 2]

It seems like there is an invisible element after 6 Can anybody tell me why is that happened?

Answer 1

Where did you get what should be [5,3,1]?

Reminder:
Slice = [From:Before:Step]

If you want it to be [5,3,1]:
print(x[-2::-2])

Answer 2

print(x[::-2])

# syntax [start : end : step]

in your case you omitted the arguments "start" and "end" so python will treat it as
[len(x)-1 : 0 : -2]

means
print(x[5 :0 : -2])

that's why it's printing [6, 4, 2]