python_introduction/learning_python3.md

121 lines
4.0 KiB
Markdown

# What we'll learn
You'll learn **three** things at the same time so don't get discouraged if it feels a bit much at the start.
Everybody's issues will be in these three different domains and at the beginning it can be difficult to differentiate between them.
Keep this in mind, everybody has to go through this stage and the *click* comes at different times for different people but everybody clicks at some point!
The three new things you'll learn:
1. the **concepts** of programming, most notably Object Orientated Programming (OOP)
2. the **syntax** of one particular language, in our case Python3
3. the **tools** needed to start programming in our language of choice
Within each of these topics there are *subtopics* but there are not bottomless!
Below is a small overview of how I would subdivide them.
## Concepts
The subtopics behind the concept of programming can be sliced (in no particular order) as follows:
* objects
* variables
* conditional logic
* functions
* loops
The concept behind these topics are the same in most languages, it's just *how* you write them that is different.
This *how* is part of the **syntax** of the language.
## Syntax
> In computer science, the syntax of a computer language is the set of rules that defines the combinations of symbols that are considered to be correctly structured statements or expressions in that language.
> This applies both to programming languages, where the document represents source code, and to markup languages, where the document represents data.
> The syntax of a language defines its surface form.[1] Text-based computer languages are based on sequences of characters,
The quote above is taken shamelessly from [wikipedia](https://en.wikipedia.org/wiki/Syntax_(programming_languages)).
## Tools
### Writing code
Scripts are text files, plain and simple.
So in order to **write** a Python3 script all we need is a text editor.
Nano, vim, notepad++ all do a good job of editing plain text files but some make it *easier* than others.
You've noticed that vim colors the code of a shell script no?
One of the many features of an [IDE](https://en.wikipedia.org/wiki/Integrated_development_environment) is *syntax highlighting*.
It colors things such as [keywords](https://realpython.com/python-keywords/) which makes our life so much nicer when writing code.
We'll come back to these features in a bit.
### Running code
In order to **run** Python3 code you need the Python3 interpreter.
This is because when you **execute** your script, the interpreter will **read and execute** each line of the text file **line by line**.
Most people who want to write and run Python3 code, or any language for that matter, will install an Integrated Development Environment to do so.
There are no *rules* as to what has to be included for a program to qualify as an IDE but in my opinion they should include:
* syntax highlighting
* autocomplete
* *goto* commands such as goto definition, goto declaration, goto references
* automatic *pair* opening and closing
* builtin help navigation
There is a plethora of IDE's available and you can't really make a *wrong* choice here, but to make the overall learning curve a bit less steep we'll start out with a user friendly IDE, [pycharm](https://www.jetbrains.com/help/pycharm/installation-guide.html).
# The python3 shell
TODO animated overview of the shell and the world of OOP
# Installing pycharm
TODO
# Your first project
TODO helloworld
## Simple printing
## String formatting
## String replacement
# Taking input
TODO say hello program
## Functions can return something
# Taking input and evaluation
TODO say hello plus ask for age
## Conditional logic
## Class string methods
# Coding challenge - Celsius to Fahrenheit converter
# Creating your own functions
TODO pretty_print
## Functions that *do* something
## Functions that *return* something
# Writing your first library
TODO import pretty print
## What are libraries?
## How do we write libraries?
## What is `__name__ == "__main__"`?
# Using the standard library
TODO import random exercise