CODEWITHSUNDEEP
pythonmethodsmoduleinvoke
noamt
noamt

Reputation: 7835

How to invoke a Python method using its fully qualified name?

In Java I can invoke a class or method without importing it by referencing its fully qualified name:

public class Example {
    void example() {

        //Use BigDecimal without importing it
        new java.math.BigDecimal(1);
    }
}

Similar syntax will obviously not work using Python:

class Example:
    def example(self):

        # Fails
        print(os.getcwd())

Good practice and PEP recommendations aside, can I do the same thing in Python?

Upvotes: 7

Views: 1367

Answers (4)

VBobCat
VBobCat

Reputation: 2732

Very late, but in case someone finds it useful, I've been using:

def fqn_import(fqn: str):
    module_name, _, function_name = fqn.rpartition('.')
    return getattr(importlib.import_module(module_name), function_name)

Upvotes: 2

Alex Hall
Alex Hall

Reputation: 36043

A function does not exist until its definition runs, meaning the module it's in runs, meaning the module is imported (unless it's the script you ran directly).

The closest thing I can think of is print(__import__('os').getcwd()).

Upvotes: 4

Chris
Chris

Reputation: 22973

No. If you want to use a module in Python, you must explicit import it's name into the scope. And, as @AlexHall mentioned, a class/function/module does not exist until import time. There's no way to accesses it without import-ing. In my opinion however, this makes for better and more explicit code. This forces you to be explicit when importing module names.

Upvotes: 2

Luftzig
Luftzig

Reputation: 523

I'm not sure that you can do exactly the same, but you can import only the function:

from foo.bar import baz as baz_fn

baz_fn()

where foo.bar is the fully qualified name of the module that contains the function and baz is the name of the function you wish to import. It will import it as the name baz_fn.

Upvotes: 1

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