# Creating Modules

### **Code Containers**

**Function** simplest form of code containers we discussed it before

**Class** is a collection of functions 

**Module** is a file which contains various Python functions and global variables. It is simply just .py extension file which has python executable code.

**Package** is a collection of modules. It must contain an **init**.py file as a flag so that the python interpreter processes it as such. The **init**.py could be an empty file without causing issues.

**Library** is a collection of packages.

**Framework** is a collection of libraries. This is the architecture of the program.

### **What's Module** 

A file containing a set of functions you want to include in your application.

### Create a Module

To create a module just save the code you want in a file with the file extension `.py`:

Save this code in a file named `module.py`

```
def greeting(name):
  print("Hello, " + name)
```

### Use a Module

Now we can use the module we just created, by using the `import` statement:

```
import module

module.greeting("Ayman")

Output:
Hello, Ayman
```

### Variables in Module

The module can contain functions, as already described, but also variables of all types (arrays, dictionaries, objects etc):

Save this code in a file named `module.py`

```
person = {
  "name": "John",
  "age": 36,
  "country": "Norway"
}
```

Import the module named mymodule, and access the person dictionary:

```
import module

a = mymodule.person["age"]
print(a)
```

### Naming a Module

You can name the module file whatever you like, but it must have the file extension `.py`

### Re-naming a Module

You can create an alias when you import a module, by using the `as` keyword:

```
import module as mx
```

### Built-in Modules

There are several built-in modules in Python, which you can import whenever you like.

[check official documentation for all modules](https://docs.python.org/3/py-modindex.html)

### Import From Module

You can choose to import only parts from a module, by using the `from` keyword.

```
from module import person
```

> When importing using the `from` keyword, do not use the module name when referring to elements in the module. Example: `person["age"]`, **not** `mymodule.person1["age"]`