append vs extend

Question

What is the difference between .append and .extend?
Which one used for what??

Answer 1

Just like brains said, Append includes x element into existing list ex.
a = 1
list1 = [1, 2, 3]
list1.append(a) = [1,2,3,1]

and with extend
list1 = [1,2,3]
list2 = [1,1,1]
list1.extend(list2) = [1,2,3,1,1,1]

but if you'd use append in the previous case instead of extend.
list1 = [1,2,3]
list2 = [1,1,1]
list1.append(list2) = [1,2,3,[1,1,1]]

Answer 2

append includes an element in a list,extend concatenates or joins lists

Answer 3

https://stackoverflow.com/questions/252703/difference-between-append-vs-extend-list-methods-in-JUMP_LINK__&&__python__&&__JUMP_LINK

Answer 4

the method extend works as a list concatenation.

following the examples of of Markus,

list1=[1,2,3]
list2=[4,5,6]
list1.extend(list2)=[1,2,3,4,5,6]

works same as + operation,
list1=[1,2,3]
list2=[4,5,6]
print(list1+list2)