An extemely short introduction to Python

General information
- High-level scripting language
- Dynamic and strong typing
- Implemented in C (as is NumPy/SciPy)
- Extremely widespread: Google (YouTube, Google Brain, DeepMind), Dropbox, Microsoft, Intel are the largest supporters
- Clear, simple syntax
- Mostly object-oriented, but has a lot of functional influence
- Named after Monty Python, not the animal!
- First released in 1991
- Often compared with Ruby or Perl; in contrast to Ruby...
- Works on different platforms: Windows, Linux, mac OS, x86, ARM, microcontrollers, ...
Applications
- Literally everything and everywhere
Tooling:
- python (useful: the -i flag)
- ipython (useful: who and whos, ?)
- Jupyter Notebook
- PyCharm (also Community Edition)
- Spyder
- pip and conda
Python 3 vs Python 2:
- UTF-8 as default source file encoding
- Syntax: print function
- Semantics: Laziness, integer division
- Unicode strings by default + separate bytes and bytearray classes
- python vs python3 on Linux
Libraries:
- NumPy
- SciPy
- SymPy
- matplotlib
- python-control
- scikit-learn, scikit-image, astropy, ...
- Keras, TensorFlow, Theano
- Numba
Finding information:
- Be careful about the docs version (e.g. use the latest NumPy/SciPy docs, Python 3.6 etc.)
- Use Zeal or Dash
- Use StackOverflow (just google in English)
- There always is a solution for your problem!
- Read docstrings / use help() or ?
- NumPy/SciPy: If in doubt, read the source
Best practices:
- Zen of Python (PEP 20)
- PEP 8
- Hard tabs vs spaces: Use 4 spaces, full stop
- Flat source code: Use list/set/dict comprehensions and generators
Python basics
- Syntax:
  - definition of variables and functions, default, named and positional args
  - import statements
  - indexing and slicing
  - branches
  - loops
  - IO (print)
  - strings and string interpolation
- Operators and statements:
  - not
  - @
  - **
  - _ when unpacking
  - None as a nil value
  - pass
- Data structures:
  - tuples, tuples unpacking
  - lists
  - dicts
  - sets
  - ndarrays
- Misc:
  - list comprehensions
  - iteration, enumerate, zip
  - functions are first-order citizens
  - laziness: e.g. map, list
- Naming conventions
  - snake_case and SCREAMING_SNAKE_CASE
  - Underscores magic _
- Special symbols:
  - __version__
  - __init__()
  - __name__
- Classes and objects: a completely different story
- Pitfalls:
  - mutable objects as default args
  - closures capture references (late binding)

mp4096/python_intro.md

An extemely short introduction to Python