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Idan Bar-Dov
1,371 Pointsslice without parameters vs. equal
Around 5:47, Kenneth creates a copy of messy_list by using slice, as follows: clean_list = messy_list[:]
What is the purpose of using slice here? dropping the slice part, as follows, seems cleaner. clean_list = messy_list
1 Answer
Cheo R
37,150 PointsTake a look at:
lst = list(range(50))
also_lst = lst
new_lst = lst[:]
print("lst id: ", id(lst)) # lst id: 139777404330952
print("also_lst id: ", id(also_lst)) # also_lst id: 139777404330952
print("new_lst: ", id(new_lst)) # new_lst: 139777411441160
print(also_lst is lst) # True
print(new_lst is lst) # False
Where the former assigns to variables to the same object (they both point to lst). The latter is assigned (points to) a new list (copied). The is operator tests if two variables point the same object, not if two variables have the same value