Python 直接从命令行运行外部库 class

Question

So imagine i have an external lib called printer with one file that looks like this.

# in file ExternalLibPrinter.py
def main():
   print("hello external lib")
 

if __name__ == "__main__":
    main()

Now i've installed this via pip.

What I would like to do is run that main function. If this was a python file that in my directory i would simply run

python3 ExternalLibPrinter.py

but I cant find such a file. I've also tried

python3 printer/ExternalLibPrinter.py

This can't find that file either. So is this not possible?

Answer 1

Use this code to call the main function:

import printer.ExternalLibPrinter as printer
printer.main()

If however the main() function was in the module's __init__.py , you would call it this way:

import printer
printer.main()

If you want to know where are the library's files stored, do this:

$ python3
>>> import printer
>>> printer
<module 'printer' from '/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/printer/__init__.py'>

In this example it shows where printer is installed on my computer, but that may be different with yours.

If the library is a single file, it will be called printer.py . If is is in multiple files, there will be a directory named printer which will contain: __init__.py — File that is used when you write import printer and for each submodule there will be a file submodulename.py that is used when you write import printer.submodulename .