Python: list of lists

Question

Running the code

listoflists = []
list = []
for i in range(0,10):
    list.append(i)
    if len(list)>3:
        list.remove(list[0])
        listoflists.         


        

Answer 1

The list variable (which I would recommend to rename to something more sensible) is a reference to a list object, which can be changed.

On the line

listoflists.append((list, list[0]))

You actually are only adding a reference to the object reference by the list variable. You've got multiple possibilities to create a copy of the list, so listoflists contains the values as you seem to expect:

Use the copy library

import copy
listoflists.append((copy.copy(list), list[0]))

use the slice notation

listoflists.append((list[:], list[0]))