Home Backend Development Python Tutorial Why Do Lambdas Within Loops in Python Share State?

Why Do Lambdas Within Loops in Python Share State?

Nov 18, 2024 am 05:53 AM

Why Do Lambdas Within Loops in Python Share State?

Lambdas within Loops: Addressing Shared State

In Python, lambdas created within a loop can exhibit unexpected behavior due to shared state. As an example, consider the following code that aims to create lambdas that access an object's property:

lambdas_list = []
for obj in obj_list:
   lambdas_list.append(lambda : obj.some_var)
Copy after login

However, upon iterating through and calling these lambdas, the last object's property value is always obtained:

for f in lambdas_list:
    print(f())
Copy after login
Copy after login

To address this limitation, a simple modification can be made:

lambdas_list.append(lambda obj=obj: obj.some_var)
Copy after login

By providing a default argument to the lambda, the current value of the object is captured at the time of creation. This ensures that each lambda retains its own state, and the desired results are obtained:

for f in lambdas_list:
    print(f())
Copy after login
Copy after login

The above is the detailed content of Why Do Lambdas Within Loops in Python Share State?. For more information, please follow other related articles on the PHP Chinese website!

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

Hot Article Tags

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

How Do I Use Beautiful Soup to Parse HTML? How Do I Use Beautiful Soup to Parse HTML? Mar 10, 2025 pm 06:54 PM

How Do I Use Beautiful Soup to Parse HTML?

Image Filtering in Python Image Filtering in Python Mar 03, 2025 am 09:44 AM

Image Filtering in Python

How to Download Files in Python How to Download Files in Python Mar 01, 2025 am 10:03 AM

How to Download Files in Python

How to Use Python to Find the Zipf Distribution of a Text File How to Use Python to Find the Zipf Distribution of a Text File Mar 05, 2025 am 09:58 AM

How to Use Python to Find the Zipf Distribution of a Text File

How to Work With PDF Documents Using Python How to Work With PDF Documents Using Python Mar 02, 2025 am 09:54 AM

How to Work With PDF Documents Using Python

How to Cache Using Redis in Django Applications How to Cache Using Redis in Django Applications Mar 02, 2025 am 10:10 AM

How to Cache Using Redis in Django Applications

How to Perform Deep Learning with TensorFlow or PyTorch? How to Perform Deep Learning with TensorFlow or PyTorch? Mar 10, 2025 pm 06:52 PM

How to Perform Deep Learning with TensorFlow or PyTorch?

Introducing the Natural Language Toolkit (NLTK) Introducing the Natural Language Toolkit (NLTK) Mar 01, 2025 am 10:05 AM

Introducing the Natural Language Toolkit (NLTK)

See all articles