4.3. Storing Functions in Module

One advantage of functions is the way they separate blocks of code from your main program. You can store your function also in a separate file called a module and then importing that module into your main program. An import statement tells Python to make the code in a module available in the currently running program file.

Importing an Entire Module

To start importing functions, we first need to create a module. A module is a file in .py that contains the code you want to import your program. Let's make a module that contains the function make_pizza().

> Adding * allows the function to accept more than one arguments.

Now, in our main.py, we can import the module in pizza.py and then makes two calls to make_pizza().

To call a function from an imported module, enter the name of the module you imported, pizza, followed by the name of the function, make_pizza(), separated by dot ..

Each function in the module is available through the following syntax:

module_name.function_name()

> When Python reads this file, the line import pizza tells Python to open the file pizza.py and copy all the functions from it into this program.

Importing Specific Functions

You can also import a specific function from a module. Here's the general syntax for this approach:

from module_name import function_name

You can import as many functions as you want from a module by separating each function's name with a comma:

from module_name import func_0, func_1

The previous example would look like this if we want to import just the function we're going to use:

> With this syntax, you don't need to use the dot notation when you call a function. Because we've explicitly imported the function make_pizza() in the import statement, we can call it by name when we use the function.

Using as to Give a Function an Alias

You can use a short alias (an alternate name, like a nickname) for the function. Here we give the function make_pizza() an alias, mp(), by importing make_pizza as mp. The as keyword renames a function using the alias you provide.

The general syntax for providing an alias is:

from module_name import function_name as fn

> The import statement shown here renames the function make_pizza() to mp() in this program. Any time we want to call make_pizza() we can simply write mp() instead.

Using as to Give a Module an Alias

You can also provide an alias for a module name. Giving a module a short alias, like p for pizza, allows you to call the module's functions more quickly.

The general syntax for this approach is:

import module_name as mn

> The module pizza is given the alias p in the import statement. Calling the functions by writing p.make_pizza() will be more concise than writing pizza.make_pizza().

< Prev. Lesson

Next Lesson >

Exercise 4.3

Make Sandwich
Make a similar function as make_pizza() called order_stationary(). The first argument is the name of the person who is ordering. The second argument and on are the stationary (pen, pencil, etc.) Put the functions in a separate file called ordering.py. (Click the + button on far right to make a new file) Write an import statement at the top of main.py and modify the file to use the imported functions.
Imports
Import the function you made in no. 1 into your main program file using these four approaches. Then, call the function (once each).
- import module_name
- from module_name import function_name
- from module_name import function_name as fn
- import module_name as mn
  from module_name import *

Page updated

Google Sites

Report abuse