# Python Modules

> Learn how Python modules work: every file is a module you can pull in with import or from .. import, and how __init__.py turns a folder into a package.

Author: [Flavio Copes](https://flaviocopes.com/about/) | Published: 2020-12-25 | Topics: [Python](https://flaviocopes.com/tags/python/) | Canonical: https://flaviocopes.com/python-modules/

Every [Python](https://flaviocopes.com/python-introduction/) file is a module.

You can import a module from other files, and that's the base of any program of moderate complexity, as it promotes a sensible organization and code reuse.

In the typical Python program, one file acts as the entry point. The other files are modules and expose functions that we can call from other files.

The file `dog.py` contains this code:

```python
def bark():
    print('WOF!')
```

We can import this function from another file using `import`, and once we do, we can reference the function using the dot notation, `dog.bark()`:

```python
import dog

dog.bark()
```

Or, we can use the `from .. import` syntax and call the function directly:

```python
from dog import bark

bark()
```

The first strategy allows us to load everything defined in a file.

The second strategy lets us pick the things we need.

Those modules are specific to your program, and importing depends on the location of the file in the filesystem.

Suppose you put `dog.py` in a `lib` subfolder.

In that folder, you need to create an empty file named `__init__.py`. This tells Python the folder contains modules.

Now you can choose, you can import `dog` from `lib`:

```py
from lib import dog

dog.bark()
```

or you can reference the `dog` module specific function importing from `lib.dog`:

```py
from lib.dog import bark

bark()
```