What is the meaning of int a -1 in Python duplicate

Question

I don't get this at all. In people's coding, I have observed this. yet unable to determine what it does. Python is the language im using: 

str(int(a[::-1]))

Answer 1

I'll assume that an is a string. Python's Slice notation has the syntax -

list[<start>:<stop>:<step>]

As a result, when you perform a[::-1], each element is taken from the end to the beginning. So it turns an around. This also applies to lists and tuples.

As an illustration

>>> a = '1234'

>>> a[::-1]

'4321'

The string is returned after you convert it to an int and then back to a string (although I'm not clear why you do that).

Answer 2

I'm not sure i understand why it's written this way but here's what it does. 

`a[::-1]` returns the list `a` in reverse order (`::` means reverse, `-1` means include the zeroth element)

`int()` casts the argument as an integer

`str()` casts its argument as a string

However, the call `str(int(a[::-1]))` fails, because `int()` expects a string, a bytes-like object or a number as its argument, not a list