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Chapter 7: Using existing functions

Importing modules

face Josiah Wang

Python provides more than the standard built-in functions.

For example, Python provides a math module containing many common mathematical functions.

A module is a file somewhere on your hard drive that contains a collection of functions and variables (among other things) that are usually related to each other. We will discuss more about modules in future lessons.

To use the functions in a module, you will first have to import the module to your program.

You simply use the import keyword to do this.

For example, the code below imports the math module.

>>> import math

This will create a module object called math.

>>> math
<module 'math' (built-in)>
>>> type(math)
<class 'module'>

The module object contains the functions and variables as defined in the module.

To access one of these variables or functions, use the name of the module, followed by a dot, and followed by the variable/function name. This is known as “dot notation”.

>>> math.sqrt(9)
3
>>> math.pi
3.141592653589793