How to use external modules in Python – with examples

  • Reading time:16 mins read

What can we use for External Modules in Python?

A module can simply be defined as any file that contains Python code and is stored with a .py extension. For example, a file named that contains Python statements and definitions can be referred to as a Python module named example.

How can you use External Modules in Python?

External modules in Python are important since they allow developers to break down large programs into small manageable files. Furthermore, modules also allow developers to reuse code.

Once a Python file has been imported as a module into another file it gives us access to its classes and functions.  

external modules in Python

Although Python gives developers access to a large number of inbuilt modules, we can also create custom modules by defining our own functions and statements in a module and then importing them instead of rewriting them all over again.

Download and install External Modules in Python

External modules in Python can also be downloaded and installed using pip which is a package manager. On the other hand, some modules such as the Math module need no installation. We just need to use the word import followed by the module name. As shown below.

import math

This will give us access to all the functions, classes and statements if any that are within the Math module. So for instance, if we use the keyword ‘math’ followed by a dot we can have access to a list of all functions within the Math module.

As shown below. Using the same principle we can create our own modules and import them quite simply into any file and use their functions as we deem fit.  


external modules in Python  

Using the Sayhey module in Python

The first module that we are going to create is called ‘’. The module is going to contain a very simple function that takes in a variable that we are going to call an animal and return a Hello statement.  




Not a particularly complicated one but we can actually import this into a different file and get access to this function within the other file.

Conventionally, we normally do the importing at the top of the other file that we are importing into. In this case, the file that we are importing into is named ‘’.  



As shown above, it is not particularly complicated and as shown once we have imported the module sayhey, we now have access to the sayhey.say() function within the other file.

Although the function is not precisely declared in that file, once we pass the argument ‘John’ to the function and run the code we have the Hello statement printed alongside the name John. 

Now conversely we can also import data from another Python file. In this case, we are going to import a list of animals from a file named ‘’.   



Since we are importing a second module into the file we need not import it in another line we can chain the imports together.  


external modules in Python

Import several modules at the same file

Now using the two modules that we have just imported we are going to write a for loop that iterates over the list in the module that we have just imported.

Using the say() function from the sayhey module we can print out the hello statement alongside the names of the animals from the list.  



This is how to use external modules in Python. If you’d like to see more programming tutorials, check out our Youtube channel, where we have plenty of Python video tutorials in English.

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