Starting up with Python – Part 11

We have now reached yet another interesting part of the Python tutorial on building your own functions and default parameters.

• Seven steps to compile Python 3.5.0 from source
• Getting started with Python and Anjuta
• Starting up with Python – Part 1 – Numbers and Maths, Variables
• Starting up with Python – Part 2 – Modules and Functions, Strings
• Starting up with Python – Part 3 – Sequences and List, Slicing and Editing
• Starting up with Python – Part 4 – More list functions and Slicing lists
• Starting up with Python – Part 5 – Methods
• Starting up with Python – Part 6 – Sort and Tuples, Strings and stuff, methods and Dictionary
• Starting up with Python – Part 7 – If statement, Else and elif statements
• Starting up with Python – Part 8 – Nesting and Comparison operators
• Starting up with Python  – Part 9 – And and Or operators
• Starting up with Python – Part 10 – While, For, Infinite and Break Loops

25. Building functions

We have been using several built-in functions in Python. This time we are going to build our own functions. We will start by defining the function – see line1. After having defined the function, we will need to tell the function what to do. Here is an example where a function is created and instructed what to do.

>> def hackers(x):
... return 'whats up mauritius' + x

Now, the function is used just by inserting the following line. As you can see it returns friends by using the function hackers.

>> print hackers(' friends')
whats up mauritius friends

Another example where a function can be created is by adding a specific number.

>> def addition(z):
... return z+10
... 
>>> print addition(10)
20

26. Default Parameters

Default parameter in the functions is used instead of having a default value. Here is an example of a simple basic function which takes two parameters.

>> def continent(east,west):
... print '%s %s' % (east, west)
... 
>>> continent('australia', 'africa')
australia africa

Now, the function has rewritten a function that already has default values in it. Here is an example. We also noticed that the continent function gave the value Australia and Africa directly.

>> def continent(east='australia', west='africa'):
... print '%s %s' % (east, west)
... 
>>> continent()
australia africa

But what if we want to overwrite Africa and use Madagascar instead? Here is the catch. Whenever a specific value is given, it will overwrite the default value otherwise use the default values

>> continent('australia','madagascar')
australia madagascar
>>> continent()
australia africa 

You can also overwrite default values as such:

>> continent(west='usa')
australia usa