CODEWITHSUNDEEP
pythonpython-3.x
simonzack
simonzack

Reputation: 20928

Python import all module object

I have the following files:

./main.py
./lib/__init__.py
./lib/lib.py

,

$ cat lib/lib.py

def method():
    return 'method'

,

$ cat lib/__init__.py

from .lib import *

,

$ cat main.py

import lib

def main():
    print(lib.lib)

if __name__=='__main__':
    main()

I don't know why lib.lib is defined, it's not a variable in the lib.py file. Any ideas?

Upvotes: 2

Views: 577

Answers (1)

Martijn Pieters
Martijn Pieters

Reputation: 1121924

The lib.lib object is the nested lip.py file inside the lib package.

Once you have imported the sub module, it also becomes available as an attribute of the package (unless you also included a lib name in the __init__.py file.

The Python 3.3 module loader (which is implemented in Python) simply sets a nested module as an attribute on the parent:

# [find a loader and load the module object, setting sys.modules[name]]
module = sys.modules[name]
if parent:
    # Set the module as an attribute on its parent.
    parent_module = sys.modules[parent]
    setattr(parent_module, name.rpartition('.')[2], module)

This behaviour is more or less implied in the Python packages documentation:

All modules have a name. Subpackage names are separated from their parent package name by dots, akin to Python’s standard attribute access syntax. Thus you might have a module called sys and a package called email, which in turn has a subpackage called email.mime and a module within that subpackage called email.mime.text.

Upvotes: 3

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