my_python_notes

Introductory CSCI notes for the Python programming language

Much of the material in this repository is taken from the MITx course Introduction to Computer Science and Programming Using Python (6.00.1x)

Much of what's in this repo is copied and pasted from class slides and transcripts, but I have arranged, re-arranged, explained, re-explained, commented, and changed comments to make it easier to understand. In other words, the contents of these files are either very different to the original class material or essentially the same and don't provide anything new, depending on how you want to look at it. Simply put: these are simply my personal notes and they are arranged and edited in a way that is convenient for me; no claims are made and no guarantees are given.

If you want the complete course material this is not a good place to look. By a standard of "having all the notes to help me can pass the class" this repo would be disorganized, incomplete in some ways, and too expansive in other ways.

Note: the course is organized in units that contain lectures that contain videos and exercises. I refer to the videos as "segments" and give them their own numbering. (The website numbers everything sequentially, but that doesn't make clear that the exercises are related to the video.)

Contents

OOP

• oop_basic_concepts.md: basic concepts of Object-Oriented Programming (e.g. methods, classes)

• intro_graph_problems.md: a application of OOP—usage of methods, classes, subclasses—to solve some basic graph optimization problems

language_basics

• for_loop_examples.md: the purpose of this document is to give some simple examples of for loops and show some of their characteristics in Python. This will hopefully serve to contrast with how for loops behave in other languages

• string_slicing.md: an explanation of how slicing works

recursions

• basic_examples_recursion.md

• recursions_unit_2_lesson_4.md contains all (or most) of the material regarding recursions presented in the course.

  • recursions_u2l4_CODE_part_1.py (and ...part 2) have the same code as the markdown but are ready to use in python

• genSubsets_explanation.md contains a recursion to generate subsets from a list. This was seen in one of the latter lessons of the course and presented mostly to talk about complexity of the code (exponential running time as size of the input gets larger). The explanation in this page is much more detailed than anything that was given. There is a .py file with the code ready for running

abstraction

I found the following quote by Edsger Dijkstra fascinating:

" ... the effective exploitation of his powers of abstraction must be regarded as one of the most vital activities of a competent programmer. In this connection it might be worth-while to point out that the purpose of abstracting is not to be vague, but to create a new semantic level in which one can be absolutely precise."

so I dug into the subject a little more, starting with notes from the class.

• abstraction.md: introductory notes, with a more practical sense, on function definitions and the basic concepts of decomposition and abstraction

• abstraction_2.md: more theoretical notes from an old book by Barbara Liskov and John Guttag in which they talk about the need for decomposition and abstraction and show its application in the CLU language (a precursor to many modern programming languages)

• abstraction_3_procedural.md: deeper into the theory seen in file 2

complexity

• 1_asymp_notation.md: a description of how asymptotic notation works, and what "Big O" and "Big Theta" notations represent

• 2_merge_sort.md: a description of how the merge sort algorithm works and an analysis of its complexity