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Python: Create a deep copy of a given list

Python module: Exercise-2 with Solution

Write a Python program to create a deep copy of a given list. Use copy.copy

Sample Solution:

Python Code:

import copy
nums_x = [1, [2, 3, 4]]
print("Original list: ", nums_x)
nums_y = copy.deepcopy(nums_x)
print("\nDeep copy of the said list:")
print(nums_y)
print("\nChange the value of an element of the original list:")
nums_x[1][1] = 10
print(nums_x)
print("\nCopy of the second list (Deep copy):")
print(nums_y)
nums = [[1, 2, 3], [4, 5, 6]]
deep_copy = copy.deepcopy(nums)
print("\nOriginal list:")
print(nums)
print("\nDeep copy of the said list:")
print(deep_copy)
print("\nChange the value of some elements of the original list:")
nums[0][2] = 55
nums[1][1] = 77
print("\nOriginal list:")
print(nums)
print("\nSecond list (Deep copy):")
print(deep_copy)

Sample Output:

Original list:  [1, [2, 3, 4]]

Deep copy of the said list:
[1, [2, 3, 4]]

Change the value of an element of the original list:
[1, [2, 10, 4]]

Copy of the second list (Deep copy):
[1, [2, 3, 4]]

Original list:
[[1, 2, 3], [4, 5, 6]]

Deep copy of the said list:
[[1, 2, 3], [4, 5, 6]]

Change the value of some elements of the original list:

Original list:
[[1, 2, 55], [4, 77, 6]]

Second list (Deep copy):
[[1, 2, 3], [4, 5, 6]]

Flowchart:

Flowchart: Create a deep copy of a given list.

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Python Code Editor:

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Previous: Write a Python program to create a shallow copy of a given list.
Next: Write a Python program to create a shallow copy of a given dictionary.

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Python: Tips of the Day

For-else construct useful when searched for something and find it:

# For example assume that I need to search through a list and process each item until a flag item is found and 
# then stop processing. If the flag item is missing then an exception needs to be raised.

for i in mylist:
    if i == theflag:
        break
    process(i)
else:
    raise ValueError("List argument missing terminal flag.")