Home > Backend Development > Python Tutorial > Python's 'is' Operator: Identity vs. Equality—What's the Difference?

Python's 'is' Operator: Identity vs. Equality—What's the Difference?

Linda Hamilton
Release: 2024-12-14 00:41:09
Original
895 people have browsed it

Python's

The Misconception of the "is" Operator

The "is" operator in Python is often misunderstood. Contrary to its name, it does not compare the values of variables; instead, it evaluates the identity of objects.

Understanding Object Identity

Objects in Python are unique entities identified by their memory addresses. When you create two separate variables and assign them the same value, you're not creating two copies of the same object but rather creating two distinct objects with the same content.

The "is" Operator Tests Identity

The "is" operator checks if two variables refer to the same object in memory. It returns True if they point to the exact same instance, even if they hold identical values. To compare the values of two variables, use the "==" operator instead.

Example

Consider the following instance where we assign a list to two variables:

x = [1, 2, 3]
y = [1, 2, 3]

print(x is y)  # Output: False
Copy after login

The output is "False" because while both x and y have the same content, they are two distinct objects in memory.

Implications for Object Modification

If you modify one of the variables, the other variable remains unchanged since they don't refer to the same object. For instance:

x[0] = 4
print(y)  # Output: [1, 2, 3]
Copy after login

The value of y remains unchanged even though x has been modified.

Conclusion

The "is" operator tests object identity, not value equality. To compare the values of variables, use the "==" operator. Understanding this distinction is crucial for working effectively with objects and variables in Python.

The above is the detailed content of Python's 'is' Operator: Identity vs. Equality—What's the Difference?. For more information, please follow other related articles on the PHP Chinese website!

source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Latest Articles by Author
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template