things I wish I knew starting python

Python_Things_I'm_glad_I_know

Things I wish I knew when starting python
improve the basic interpreter

PYTHONSTARTUP is an environment variable you can use to fix the command prompt, i.e. provide autocomplete via tab, and suggestions.

    set $PYTHONSTARTUP=~/.pythonstartup in .bashrc
        export PYTHONSTARTUP=~/.pythonstartup
        turn off creation of .pyc files
            PYTHONDONTWRITEBYTECODE=1 
        enable auto-complete in the REPL

                import rlcompleter
                import readline

                # To allow tab completion
                readline.parse_and_bind("tab:  complete")

                # Include the following lines to enable peristent command history
                # # (saved to ~/.python_history)
                import os, atexit
                readline_history_file = os.path.join(os.path.expanduser('~'), '.python_history')
                try:
                    readline.read_history_file(readline_history_file)
                except IOError:
                    pass
                readline.set_history_length(3000)
                atexit.register(readline.write_history_file, readline_history_file)

    look at these resources:
        https://docs.python.org/2/using/cmdline.html#envvar-PYTHONSTARTUP 
        http://www.cs.berkeley.edu/~russell/classes/cs188/f14/faq.html  

other interpreters

    bpython (colors and doc prompts)
    ipython (never leave ipython; use it like a system prompt)
    ipython notebook (store mathematica-like notebooks that contain your python) 

Resources for learning Python

    exercism http://exercism.io/
    Learn Python the Hard Way http://learnpythonthehardway.org/book/
    Raymond Hettinger's twitter: https://twitter.com/raymondh?lang=en
    pyvideo.org
    Hitchiker's guide to Python: http://docs.python-guide.org/en/latest/
    talkpython: https://talkpython.fm/
    Real Python: https://realpython.com/ 

Debugging tools

    pdb, like gdb but for python (python -m pdb <mypythonscript.py>)
    pudb, for bringing back 90's pascal, but having watch windows. (pip install-able) 

linting tools

They are pip installable!

    flake8 https://dev.to/sethmichaellarson/linting-as-lightweight-defect-detection-for-python
        flake8 <dir> 
    pylint 

virtual environments

    I still like just virtualenv, but YMMV 

use virtualenvwrapper

    try using the system one before pip install
    pipenv is the new-hotness: https://docs.pipenv.org/
    vex helps manage virtualenvs if not using bash; https://pypi.python.org/pypi/vex 

pipenv

    https://pipenv.readthedocs.io/en/latest/ 

poetry

    https://poetry.eustace.io/ 

remove pyc files from your life

set this in your profile and .pyc files won't get created export PYTHONDONTWRITEBYTECODE=1
testing framework

    (I prefer pytest) 

    unittest (built in)
    pytest (I prefer)
    nose 

strings

    convert from unicode to ascii This ignore error conversions to ascii, but has a best guess for converting letters to an ascii equivalent.

            import unicodedata
            normed_unicode = unicodedata.normalize('NFKD', utf_string)
            ascii_string = normed_unicode.encode('ascii', 'ignore')

    "mystring: {a}".format(a)
        don't have to call 'format' immediately
        provides tools for formatting strings nicely 
    f-strings are the new, faster thing:
        f"this is my local var name: {x}" 

gotchas

    shadow variables: scoping can cause problems. use global

        x = 5
        def foo(y):
            x = 1
            print("X is: {}".format(str(x))
            y = x + 1
        print("X is: {}".format(str(x))