Swap in lineked list

swap list

How to swap elements in a list in Python
1 Swap by index
2 Swap by value

Swapping two elements changes the value at each index. 
For example, swapping the first and last elements in ["a", "b", "c"] results in ["c", "b", "a"].

SWAP ELEMENTS BY INDEX IN A LIST
Use list[index] to access the element at a certain index of a list.
Use multiple assignment in the format val_1, val_2 = val_2, val_1 to swap the value at each index in the list.

a_list = ["a", "b", "c"]
a_list[0], a_list[2] = a_list[2], a_list[0]
swap first and third element

print(a_list)
OUTPUT
['c', 'b', 'a']
SWAP ELEMENTS BY VALUE IN A LIST
Use list.index(value) with each element as value to get their indices. 
Use multiple assignment to swap the value at each index in the list.

a_list = ["a", "b", "c"]

index1 = a_list.index("a")
index2 = a_list.index("c")
a_list[index1], a_list[index2] = a_list[index2], a_list[index1]

print(a_list)
OUTPUT
['c', 'b', 'a']