The difference between append and extend in Python

append() adds the object at the end.

x = [1, 2, 3]
x.append([4, 5])
print (x)

[1, 2, 3, [4, 5]]

extend() appends the elements of an optional object (list, tuple, dictionary, etc.) to the list.

x = [1, 2, 3]
x.extend([4, 5])
print (x)

[1, 2, 3, 4, 5]