Here are a few title options that are question-based, relevant to the article\'s content, and in English: * Chained Assignments in Python: How Does It Work? * Are Chained Assignments Always Safe in

Understanding Chained Assignments in Python

Chained assignment in Python, where multiple variables are assigned to the same value in a single line, has raised questions about its behavior and the relationship between different chained assignments. This article aims to shed light on these concepts.

Leftmost Assignment Rule

Consider the chained assignment:

x = y = somefunction()

This is equivalent to the following separate assignments:

temp = somefunction()
x = temp
y = temp

It's important to note that the leftmost target is assigned first. This means that the value returned by somefunction() is assigned to the variable on the leftmost end of the chained assignment, and then that value is reassigned to the remaining variables.

Effect on Mutable Objects

When assigning mutable objects (e.g., lists, dictionaries) using chained assignments, caution is required. Consider the following:

x = y = []  # Wrong
x.append(1)
print(y)  # Prints [1]

In this case, x and y refer to the same list. Appending to x also affects y because they are aliases to the same underlying object.

Distinct Assignments

To create separate, distinct variables, it's always preferable to assign each variable to its own value:

x = []  # Right
y = []  # Right

Now, x and y are two separate empty lists.

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