shannonturner/python-lessons

First time installing/running Python? Be sure to check out the Start Here guide: https://github.com/shannonturner/python-lessons/blob/master/start-here.md

In here are code snippets, examples, and other ways to help teach some of the concepts and tricks in Python.

Slides are available to download here: https://github.com/hearmecode/slides

Suggested Learning Progression

If you're new to Python you may wonder what you should learn and when you should learn it. I recommend this order seen below. Each section below has its own folder above; each bullet point has its own file within that folder.

So if you wanted to learn more about variable assignment, go to the folder section_01_(basics) and open up variable_assignment.py

Section 1: General Programming Basics

• Simple Math
• Variable Assignment
• Basic Syntax and Logic
• Data Types: int, float, bool, str

Section 2: Strings

• Identifying and using strings
• String slicing
• String formatting
• String methods
• • str.replace()
• • str.find()
• • str.count()
• • str.lower()

Section 3: Conditionals

• Logical control; changing the behavior of your programs
• and keyword, or keyword
• if / else structure
• if / elif ... / else structure
• Nesting conditionals

Section 4: Lists

• Containers for data types
• First In, Last Out (Stack)
• Accessing specific list items through index (slice notation)
• List methods
• • list.append()
• • list.insert()
• • list.pop()
• • list.extend()
• Finding items in list (in keyword)
• Deduplicating a list using list(set(list_to_deduplicate))

Section 5: Loops

• for loop (for each item in a list: ...)
• enumerate()
• zip()
• range()
• while loop (ask each time: is this still true?)

Section 6: Strings to Lists and Vice-Versa

• str.join() (create a string from a list)
• str.split() (create a list from a string)

Section 7: File handling

• with open(filename) as textfile: ...
• file.read()
• Reading text files
• Reading CSV files
• File handling flags (r, w, b, +)
• Writing to files

Section 8: Python's Most Commonly Used Built-in Functions

• • Types (used primarily for converting one type to another)
• int()
• float()
• str()
• bool()
• list()
• set()
• dict()
• • Comparison and Calculation
• abs()
• len()
• max()
• min()
• round()
• sum()
• • Loop (Sequence) Control
• enumerate()
• range() / xrange()
• reversed()
• sorted()
• zip()

Section 9: Functions

• def keyword
• arguments
• default arguments
• *args
• **kwargs
• return keyword
• sequence unpacking (return and receive multiple values)
• namespaces

Section 10: Dictionaries

• Accessing specific dictionary items through key (looks like a slice)
• Accessing all keys as a list using .keys()
• Faking a sorted dictionary by using sorted() on the .keys()
• Accessing all values as a list using .values()
• Accessing all key, value pairs as a list using .items()
• Adding new items through .fromkeys()
• Checking for whether a key exists with .has_key
• Using .get() to safely get a key's value if it exists without getting an error if not
• Adding new items with direct assignment and .update()

Section 11: Dictionaries and Lists, together

• Accessing specific items in a nested list
• Accessing specific items in a nested dictionary
• Accessing specific items in a nested list within a dictionary
• Accessing specific items in a nested dictionary within a list
• If you can do those four above, you can handle receiving JSON API returns

Section 12: Standard Library

• import keyword
• from ... import ... as ... structure
• time
• random
• math
• re (regular expressions)
• os
• sys
• json

Section 13: External Libraries (Not necessarily in order; keep these in mind)

• Installing external libraries with easy_install
• Using easy_install to install pip (an easier / better way to install external libraries)
• requests (web crawling made easy)
• BeautifulSoup (parsing HTML)
• xlrd (Read Excel .xls files)
• xlwt (Write to Excel .xls files)
• xlsxwriter (Write to Excel .xls and .xlsx files, with additional functionality beyond xlwt)
• cherrypy (Simple, lightweight framework for serving web pages)
• psycopg2 (Connect to and issue SQL commands to your postgresql database)

Section 14: Exception Handling

• try / except syntax
• Using multiple excepts
• Recognizing the different error types
• Exception, the generic exception type (use sparingly)
• Nesting exception handling
• try / except / else syntax

Section 15: Intermediate Concepts

• List Comprehensions
• Inline Conditionals
• Generators

Section 16: Classes

• Classes
• Magic Methods