How to copy a list

How to copy a list.

Here is a step-by-step tutorial on how to copy a list in Python:

Step 1: Create a List To begin, let's create a list that we want to copy. For example, let's create a list of numbers:

numbers = [1, 2, 3, 4, 5]

Step 2: Using the Slice Operator One way to copy a list is by using the slice operator. The slice operator allows you to create a new list by specifying a range of indices from the original list. In this case, we will use the entire range of indices to copy the entire list:

new_list = numbers[:]

Explanation: The [:] notation creates a slice that includes all the elements of the numbers list. Assigning this slice to a new variable new_list creates a copy of the original list.

Step 3: Using the copy() Method Python provides a built-in method called copy() that can be used to create a copy of a list. Here's how you can use it:

new_list = numbers.copy()

Explanation: The copy() method creates a new list that contains the same elements as the original list. Assigning this new list to the variable new_list makes a copy of the original list.

Step 4: Using the list() Constructor Another way to copy a list is by using the list() constructor. This constructor accepts an iterable object (like a list) and creates a new list with the same elements:

new_list = list(numbers)

Explanation: The list() constructor takes the numbers list as an argument and creates a new list with the same elements. Assigning this new list to the variable new_list makes a copy of the original list.

Step 5: Modifying the Original List Let's say we have copied the original list using one of the above methods, and now we want to modify the original list to see if it affects the copied list:

numbers.append(6)

Explanation: We are using the append() method to add a new element, 6, to the numbers list.

Step 6: Checking the Copied List Now, let's check if the copied list (new_list) is affected by the modification of the original list (numbers):

print(new_list)

Output:

[1, 2, 3, 4, 5]

Explanation: The new_list remains unchanged even after modifying the numbers list. This confirms that the copied list is a separate, independent copy of the original list.

That's it! Now you know multiple ways to copy a list in Python. Choose the method that suits your needs best.