Python videos | Python Part 12a - Functions

Posted by Andy Brown on 25 October 2021


Instead of writing your code in a single long file you can (and should) call separate functions to handle discrete tasks. In addition to all the modules supplied by third parties, this tutorial shows you how to create your own libraries of useful functions.

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This video has the following accompanying files:

File name Type Description
Action.csv CSV file CSV file of action films
Animation.csv CSV file CSV file of animation films
Comedy.csv CSV file CSV file of comedy films
Musical.csv CSV file CSV file of musicals films
Science fiction.csv CSV file CSV file of science fiction films
Get duration function.py Python code Get film duration in human readable format
Read CSV file.py Python code Read in a CSV file of films
Get film age.py Python code Get the age of a film
WOL_functions.py Python code Module containing all functions written
Complete example.py Python code Bringing all other functions together
Doc strings.py Python code Example of document strings

Click to download a zipped copy of the above files.

After watching this video, you may like to test your understanding by doing one or more of the following exercises:

Exercise Level
Define a function to print out text with the correct length of underlining Easy
Create functions to parse a quotation into a list of words and get some statistics about them Standard
Write 3 functions to complete a system to extract countries from any given CSV file Hard

You can also download the answers to each exercise from the links above.

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This page has 1 thread Add post
Costas   Reply to CostasReply
21 Mar 22 at 14:08

Hi,

What is the difference between the function syntax used in the video: 

def FunctionName(Parameter: DataType) -> ReturnDataType:

      return [expression]

and the "usual" syntax:

def FunctionName(Parameter): 

      return [expression]

Is it just a more detailed coding syntax for clarity purpuses or there are other reasons/benefits that make it preferable for someone to use it?

Thanks

Andy B   Reply to Andy BReply
21 Mar 22 at 15:34

The main difference is that when you type in Parameter., VS Code will know that the parameter should hold a string/int/float/whatever, and come up with the appropriate methods specific to this data type.  But this is a pretty big advantage.

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