Package Discovery and __init__.py
When you work with packages in Python, the presence or absence of an __init__.py file in a directory determines how Python treats that directory during import. Historically, any directory intended to be a package must contain an __init__.py file. This file marks the directory as a Python package and enables the interpreter to import modules from it.
Python 3.3 and later introduced implicit namespace packages, which allow you to create packages without an __init__.py file. If you omit __init__.py, Python still recognizes the directory as a package, but only for the purpose of grouping subpackages and modules across multiple locations on the filesystem. This is useful for large projects or plugin systems. However, explicit packagesβthose with an __init__.pyβare still the most common and compatible approach, ensuring clear package boundaries and predictable import behavior.
Choosing between implicit and explicit packages impacts how Python discovers and loads your code:
- Explicit packages are generally preferred for most projects;
- They work reliably with standard tools;
- They make your package structure clear to both Python and other developers.
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When you work with packages in Python, the presence or absence of an __init__.py file in a directory determines how Python treats that directory during import. Historically, any directory intended to be a package must contain an __init__.py file. This file marks the directory as a Python package and enables the interpreter to import modules from it.
Python 3.3 and later introduced implicit namespace packages, which allow you to create packages without an __init__.py file. If you omit __init__.py, Python still recognizes the directory as a package, but only for the purpose of grouping subpackages and modules across multiple locations on the filesystem. This is useful for large projects or plugin systems. However, explicit packagesβthose with an __init__.pyβare still the most common and compatible approach, ensuring clear package boundaries and predictable import behavior.
Choosing between implicit and explicit packages impacts how Python discovers and loads your code:
- Explicit packages are generally preferred for most projects;
- They work reliably with standard tools;
- They make your package structure clear to both Python and other developers.
Thanks for your feedback!
