Trying to copy a list in list python to a new structure but failing to do so, same works with normal list. Please suggest the same for list of list

Question

import copy
tableData = [['apples', 'oranges', 'cherries', 'banana'],
             ['Alice', 'Bob', 'Carol', 'David'],
             ['dogs', 'cats', 'moose', 'goose']]
actualtable=[]

actualtable =copy.copy(tableData)
tableData[0][0]='banana'


print(tableData)
print(actualtable)

Why does both the lists tableData and actualtable point to the same structure. Can someone help me out!

Screenshot

that screenshot looks pretty cool, could you tell me where it's from? btw, if you replace `[Screenshot][1]` by `![Screenshot][1]`, you can embed the screenshot instead of only linking to it. — Silly Freak, May 12 '21 at 06:37

score 0 · Accepted Answer · answered May 12 '21 at 06:34

you are using a shallow copy, use deepcopy to get a different reference to list elements:

docs: https://docs.python.org/3/library/copy.html

copy.copy(x)

Return a shallow copy of x.

copy.deepcopy(x[, memo])

Return a deep copy of x.

so in your code just replace copy.copy with copy.deepcopy:

actualtable = copy.deepcopy(tableData)

and you'll get two entirely different list of lists

Trying to copy a list in list python to a new structure but failing to do so, same works with normal list. Please suggest the same for list of list

1 Answers1