How to dynamically reference imported file names in Python?

Question

Say I have:

file1 
file2
file3

Each of file1, file2, file3 have a dictionary called foo.

I have a different file named example_file that wants to read from file1, file2, file3.

from file1 import foo
from file2 import foo
from file3 import foo

# do something with file1.foo
# do something with file2.foo
# do something with file3.foo

Is there a way to do this through a loop?

for dynamic_name in something: 
   dynamic_name.foo # do something with foo
   # dynamic_name resolves to file1, file2, file3 through the loop

Essentially, I want to use the file names from the imports to reference items in the files themselves.

Is this possible?

Reti43 · Accepted Answer · 2021-10-12 01:44:37Z

1

Be careful with

from file1 import foo
from file2 import foo
from file3 import foo

because the name foo will be reassigned every time and by the end it will only point to whatever file3.foo is.

Anything of the syntax something.ofthis is the object something with the attribute ofthis. Regardless of whether something is some class or a module. You can achieve the same by doing getattr(something, 'ofthis'). You can also use dir(something) to see what available attributes your object has.

import file1, file2, file3

for f in (file1, file2, file3):
   foo = getattr(f, 'foo')

edited Oct 12, 2021 at 1:44

answered Oct 12, 2021 at 1:38

Reti43

9,8373 gold badges30 silver badges48 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Nikolas Stevenson-Molnar · Accepted Answer · 2021-10-12 16:59:14Z

0

The built-in __import__ function will allow you to import a module who's name is in a variable.

To see how this works, consider this example.

# This...
import file1

# ...is the same as this...
file1 = __import__('file1')

# ...and this
name = 'file1'
file1 = __import__(name)

What if you want to import a name from the module (from ... import ...)? Pass the names you want to import to the fromlist argument.

# This ...
from file1 import foo

# ... is the same as
file1 = __import__('file1', fromlist=['foo'])
foo = file1.foo

If you have a list of module names, you can loop through them.

names = ['file1', 'file2', 'file3']
for name in names:
    module = __import__(name, fromlist=['foo'])
    foo = module.foo
    # Do something with foo

Or you can keep a dictionary of names and modules.

names = ['file1', 'file2', 'file3']
modules = {}
for name in names:
    modules[name] = __import__(name, fromlist=['foo'])

modules['file2'].foo  # access like this

edited Oct 12, 2021 at 16:59

answered Oct 12, 2021 at 1:40

Nikolas Stevenson-Molnar

4,7502 gold badges25 silver badges31 bronze badges

2 Comments

Cuttles Over a year ago

Is there a way to use this in a loop to update what we reference? ie: file1 in iteration 1, file2 in iteration 2, etc

Nikolas Stevenson-Molnar Over a year ago

Sure. I added an example.

Collectives™ on Stack Overflow

How to dynamically reference imported file names in Python?

2 Answers 2

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related