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python list copy() method

Python List copy() Method

In this tutorial, we are going to learn the Python list copy method. list copy function in Python allows creating a copy of the existing list. Sometimes we need to create a copy of the list, Then we have the best method to copy(), which is used to create a copy of the list.

In the previous tutorial, we have seen the Python list append method and list clear method.
In this guide, we will learn how to create a copy of the list using different-2 methods.

Python list copy() method:

In Python, list copy() method is list built-in method which is used to create the copy of the list.

Syntax of the list copy() function:

list.copy()

Return type of the list copy() method:

The return type of the python list copy method is a new list, That does not modify the original list because the copy() method return a shallow copy of the list.

list copy() method parameters:

list copy method does not take any parameters.

You can create the copy of the list method using = operator for example:

old_list = [1, 2, 3, 4, 5]
new_list = old_list

The problem with creating a copy of this way is that, if you modified the new_list, the old_list will also be modified.

new_list.append(6)
print(new_list)
print(old_list

Output

[1, 2, 3, 4, 5, 6]
[1, 2, 3, 4, 5, 6]

However, if you need original list unchanged when the new list modified, you can use list copy function.

Copy list using copy() method.

Example:

fruits = ['apple', 'banana', 'cherry']
x = fruits.copy()
print(x)

Output

['apple', 'banana', 'cherry']

If you modified list x in the above example, fruits list not modified.

Copy list using slice syntax:

You can create create the copy of the list using slice syntax.

old_list = ['Python', 'C++', 'C', 'PHP']

new_list = old_list[:]
new_list.append('Java')
print('old_list:- ', old_list)
print('new_list:- ', new_list)

Output

old_list:-  ['Python', 'C++', 'C', 'PHP']
new_list:-  ['Python', 'C++', 'C', 'PHP', 'Java']

If you modified list new_list in the above example, old_list list not modified.

Conslusion:

In this tutorial, you have learned about the Python list copy() method to create a copy of the existing list. Using slice syntax and list copy method you can create a copy of the existing list, which will be a shallow copy. When you use both methods to create a copy of the list, Then your new list becomes a new separate list.

I hope this article will help you. If you like this article please comment and share with your friends who want to learn Python programming from scratch to advanced.

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