How to Avoid Circular Dependency Issues in Python Modules?

Circular Dependency in Python

Circular dependency can arise when two modules rely on each other's definitions, causing import issues. In this case, we have two Python files: node.py and path.py. Initially, path.py imported Node from node.py. However, after a new method was added to Node referencing Path, circular dependency occurred.

To resolve this issue, we can consider several approaches:

1. Conditional Import:

Import path.py only in the function where it's needed.

# in node.py
from path import Path

class Node:
    # ...

# in path.py
def method_needs_node():
    from node import Node
    n = Node()
    # ...

2. Late Binding:

Use setattr() to assign the missing class reference at runtime.

# in node.py
# Placeholder Path class
class Path:
    pass

# Importing path.py
import path

# Assigning the actual Path class after importing path.py
path.Path = load_node_module('path.Path')  # Implementation details omitted

class Node:
    # ...

# in path.py
class Path:
    # ...

The above is the detailed content of How to Avoid Circular Dependency Issues in Python Modules?. For more information, please follow other related articles on the PHP Chinese website!