execution order for swap function

Question

My naive understanding is that we need a temporary variable to perform a swapping operation. Can someone tell me how the code below can help swap without the use of any temporary variables?

def swap(i,j,array): 
    array[i], array[j] = array[j],array[i]

Note: You can find this used extensively in sorting algorithms

Answer 1

Both sides are treated as tuples, in python (and many other functional languages) you can pack and unpack them freely.

The RHS gets packed into a new tuple, the the LHS unpacks it again, but the opposite way around.

There's more on tuples and unpacking here: https://docs.python.org/3/tutorial/datastructures.html#tuples-and-sequences