I have:

1. A small python list, say list2, [2, 4, 6]
2. A large, initially empty, python list, say list1, []

What I need:

1. list2 to be added in list1 as a small list inside large list.
2. After addition all elements of small list be deleted.

The python code I have written for the purpose:

list1 = []
list2 = [2, 4, 6]
list1.append(list2)
del list2[:]
print("List 2: ", list2)
print('List 1: ', list1)

The expected output was:

List 2:  []
List 1:  [[2, 4, 6]]

But What I got is this:

List 2:  []
List 1:  []

>Solution :

You are appending list2 as a refrence. so when you apply del list2[:] it is clearing the list that was appended to list1 also.

To resolve this issue you can append list2. by first creating a copy and than appending.

Code:

list1 = []
list2 = [2, 4, 6]
list1.append(list2.copy())  
del list2[:]
print("List 2: ", list2) #[]
print('List 1: ', list1) #[[2, 4, 6]]