What happens when I use [::-1] with a variable?

Question

So I have this code:

t=int(input())
while t:
 s=int(input())
 n=bin(s)
 n=n[2:][::-1]
 if n.count('1')==1:
  pos=n.find('1')+1
  print(pos)
else:
  print('-1')
t-=1

I would like to know exactly what's going on in this line:

 n=n[2:][::-1]

What does [::-1] means?

Short answer: It's the canonical reversing slice; it returns a shallow copy of the input in reverse order. — ShadowRanger, Aug 17 '20 at 01:28
The [Python documentation](https://docs.python.org/3/) is really good. Please try to read it a little more. — Some programmer dude, Aug 17 '20 at 01:31

score 0 · Accepted Answer · answered Aug 17 '20 at 02:29

0

It takes the reverse of binary value of n excluding "0b" values in the beginning. For example if you enter 6 for value of n. The binary value would be 0b110 and reverse value excluding 0b would be 011.

answered Aug 17 '20 at 02:29

Nagmat

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What happens when I use [::-1] with a variable?

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