Python | How to copy a nested list

In the previous article, we have seen how to clone or Copy a list, now let’s see how to copy a nested list in Python.

Method #1: Using Iteration

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# Python program to copy a nested list
  
# List initialization
Input_list = [[0, 1, 2], [3, 4, 5], ]
Output = [] 
  
# Using iteration to assign values
for x in range(len(Input_list)):
    temp = []
    for elem in Input_list[x]:
        temp.append(elem)
    Output.append(temp)
  
# Printing Output
print("Initial list is:")
print(Input_list)
print("New assigned list is")
print(Output)

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Output:



Initial list is:
[[0, 1, 2], [3, 4, 5]]
New assigned list is
[[0, 1, 2], [3, 4, 5]]

 
Method #2: Using deepcopy

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# Python program to copy a nested list
import copy
  
# List initialization
Input = [[1, 0, 1], [1, 0, 1]]
  
# using deepcopy
Output = copy.deepcopy(Input)
  
# Printing
print("Initial list is:")
print(Input)
print("New assigned list is")
print(Output)

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Output:

Initial list is:
[[1, 0, 1], [1, 0, 1]]
New assigned list is
[[1, 0, 1], [1, 0, 1]]

 
Method #3: Using list comprehension and slicing

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# Python program to copy a nested list
  
# List initialization
Input_list = [[0,1,2], [3,4,5], [0, 1, 8]]
  
# comprehensive method
out_list = [ele[:] for ele in Input_list]
  
# Printing Output
print("Initial list is:")
print(Input_list)
print("New assigned list is")
print(out_list)

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Output:

Initial list is:
[[0, 1, 2], [3, 4, 5], [0, 1, 8]]
New assigned list is
[[0, 1, 2], [3, 4, 5], [0, 1, 8]]


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