What is it?

It's a small set of hacks to learn the basics of Python. Python is powerful, fast, plays well with others, runs everywhere, is friendly & easy to learn, is Open. I'm using Python 3.7.5 for this project (current LTS).

Take Aways

• Python comes on a lot of OS's by default but it's more common to find Python 2 instead of Python 3.

• Python Virtual Environments allow you to specify a specific version of Python for that use. Requires first installing virtualenv via pip install virtualenv.

  Example creation of Python Virtual Environments

  # virtualenv <folder to create> <path to desired python version install>
  virtualenv py3 -p /usr/local/bin/python3

  Example activation of Python Virtual Environments

  # <folder created above via >/bin/activate
  py3/bin/activate

  Example deactivation of Python Virtual Environments

  deactivate

• Python's package manager pip manages dependencies. It leverages a requirments.txt file detailing project dependencies.

  Example package install

  pip freeze > requirements.txt

  Example pip requirments.txt file

  cat requirements.txt

  certifi==2019.9.11
  chardet==3.0.4
  idna==2.8
  requests==2.22.0
  urllib3==1.25.7

• pip install vs. import? pip install brings the dependency local for runtime where as import uses a looked up asset via putting it somewhere python can expect it to be.

• In Python everything has a id. The id property is immutable.

• In Python everything has a value.

• Immutable vs. Mutable Types

  Class	Description	Immutable
  bool	Boolean value	✅
  int	integer	✅
  float	floating-point number	✅
  list	mutable sequence of objects
  tuple	immutable sequence of objects	✅
  str	character string	✅
  set	unordered set of distinct objects
  fronzenset	immutable form of set class	✅
  dict	associative mapping (aka dictionary)

  b = []
  b(id) # 4527447816
  b.append(3)
  print(b) # [3]

  a = 4
  id(a) # 4321639424
  a = a + 1
  id(a) # 4321639456

• Use None for null check in Python. Use a foo is None check for performance vs. slower and more process heavy foo == None as foo is None checks the id and it exits with less process needed.

• Strings

• String Manipulation

• Conditionals

• Loops

• Relational Operators

• Lists

• List Slice

• List Comprehensions

• Dictionaries

• Tuples

• Sets

• Logging

• Command Line Input

• Functions

• Modules

• Reading From A File

• Writing To A File

• Error Handling

• Scopes

• Classes

• pip useful commands

  • pip install <package-name> to install a package
  • pip list to list all packages installed to the current virtual environment
  • pip search <package-name> can be used to search packages available
  • pip list --outdated show out of date dependencies
  • pip uninstall <package-name> to uninstall package

Things I like

• Simple
• Forces good styling as there is no braces used
• Key word arguments

  def madlibs(name, noun = "shoes", adjective = "red"):
    return "{0} has {1} {2}".format(name, adjective, noun)
  madlib = madlibs("Will", adjective="black", noun="boots")
  print(madlib) # Will has black boots

Things I'm not a huge fan of

• Python's package ecosystem doesn't seem to all use Semantic Versioning (example: idna as 2.8)
• Text file for dependency details feels lackluster
• Underscore as multi word variable convention (sum_of_two_numbers = 1 + 3) 😑
• global, nonlocal, and local varibales are confusing solution that feels clumsier than just having scopes be blocked at first glance. I'm sure there's cool things you could do with it in principal, but I also feel like you'd be a jerk if you actually used them.