Python List Slices: Why Does Assignment Modify the Original List?

Assignment to List Slices: Delving into the Mechanics

In Python, slicing a list is known to return a new list. However, when assigning to list slices, we encounter seemingly paradoxical behavior. This article aims to shed light on this phenomenon and address the following questions:

• Can a returning value appear on the left side of an expression?
• Why is the original list modified despite slicing returning a new list?

Explanation:

You must distinguish between two distinct operations with схожим syntax:

1. Slicing (Return Copy Operation):

b = a[0:2]

This operation creates a copy of the slice from 'a' and assigns it to 'b'. It does not modify the original list 'a'.

2. Slice Assignment (Replacement Operation):

a[0:2] = b

In contrast to slicing, this operation replaces the slice of 'a' with the contents of 'b'. The original list 'a' is thus modified.

While the syntax may seem similar, these operations are fundamentally different.

Conclusion:

Assignment to list slices is not a contradiction but rather a specific operation that allows you to modify a portion of an existing list. By understanding the distinction between slicing and slice assignment, you can effectively utilize this syntax to manipulate lists in Python.

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