Python programming - Everyday(ish) Examples

 Python is a programming language with strengths of both functional and object-oriented
programming.
 Here I will present common problems and their solutions that you might use while
starting coding in Python.
 You may use this material as a reference.
By Ashish Sharma for Next Craft

 One who has began learning Python.
 One who has made oneself acquainted with concepts of Python taught in
codecademy.com Python course.
 One who wishes to learn the idioms of python to solve problems in pythonic way.
 One who is interested in free, good content. 

 Learn by Doing: Here are examples of python code used in different scenarios.
 You can try to pick the concepts and then mould them to use in your own
situation.
 Use of Classes, Exceptions, rest of Standard Library not covered here.

 Let us suppose we have a file containing a student’s SGPAs from 8 semesters and
we would like to write a new file with CGPA.
 SGPA.txt , has list of numbers in different lines.
 Generating CGPA.txt from SGPA.txt
 We will first read the SGPA.txt file line by line,
 Then accumulate the values into a single variable,
 Then calculate CGPA value and write that back into a new file.
Try out yourself with sample
data

Code

 Let us suppose you have a list of SGPAs on scale of 10 and from it you want to
calculate CGPA on scale of 4.
 We will do this in two ways,
 Using for loop,
 Using map, reduce (they are not as scary as they may sound)
 The ways of coding this by map, reduce etc. are less verbose and more
transportable.

Using for loop

Using Reduce
Using Map/Reduce

 In Python the data structure of Map is implemented in Dictionary.
 A map is a structure to store <key, value> relationships.
 Suppose you need to compute sum of squares of given odd numbers that can not
be smaller than 1 and larger than 99
 In the example, we will pre compute as the limits are small and return answers
from a dict.

Code.

 From the older sgpa example, if we wish to filter out the sgpa from list that were
more than 8.5.
 From the older odd_squares example, if we wish to filter out the odd squares
where the number is a multiple of 3.

 Here we will validate data sent our way with regular expressions. You can also use
them for search, match and replace.
 Suppose we want input from user to be a number, here is how to gracefully handle
this requirement.

 Unit testing is a very important aspect of software development. In Python, you
can find extensive support for unit testing you code.
 With unit testing we can test single functions, classes or whole modules.
 Having code and test separately and testable is a prime software development
requirement.
 This fact is elicited in this advice that developers get from creator of Unit testing
framework for Small talk, (one of the first or may be the first frameworks).
 I recommend that developers spend 25-50% of their time developing tests.
 Quoted from - http://www.xprogramming.com/testfram.htm

 Here is a sample of code and test files.

Please let me know in the comments if I am missing any general scenarios, which
you would like to see in the examples here.
I will be more than happy to extend this presentation.

 Python Reference – The best guide on Python out there.
 Codecademy – Beginner course on Python, totally free .
 http://learnpythonthehardway.org/ - If you want to develop a deep sense of
knowledge of Python, venture here.

Find me at @ashish424242 and @kartaa.
Checkout NextCraft’s JMP

Python programming - Everyday(ish) Examples

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