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Python Development
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Set Up Venv
***********

In project file or where you wish to start
::

    # if your default python is not preferred point to the
    # python directory where your preferred python exists
    $ python -m venv ./venv
    # where ./venv is the name of the new directory in current directory
    $ source venv/bin/activate  #start venv
    $ deactivate    #ends venv

Requirements.txt
*****************

Allows for all requirements packages (dependencies) to be loaded at one command.
Requirements text commands-
::

    export requirements.txt
    pip freeze > requirements.txt   # writes the requirements.txt file with dependencies, one on each line
    cat requirements.txt    # shows what's in requirements.txt
    import requirements.txt
    pip install -r requirements.txt   # installs all the dependencies listed in the requirements.txt file

isort
******

Automatically sort imports by type and alphabetically ::

    pip install isort
    vim <file_name>.py
    isort <file_name>.py

Requires Python 3.6 to run.

Lists vs Dictionaries vs Tuples
********************************

| L[] vs D{} vs T() maps to array vs records vs immutable collection of objects
| L[] accessed by offset, D{} accessed by key, T() accessed by offset

Python Imports
****************

Python module is a .py file and Python package is a directory/folder contains modules. In < Python 3.3
a package is a folder that contains an __init__.py file in it. This is a convenience since in Python
packages and modules need not originate in the file system.

Given the following directory::

    └── project
        ├── package1
        │   ├── module1.py
        │   └── module2.py
        └── package2
            ├── __init__.py
            ├── module3.py
            ├── module4.py
            └── subpackage1
                └── module5.py

See how python modules, classes and fuctions are imported with aboslute imports and relative imports
from the driectory above with the guidlines below

Absolute Imports
=================

::

    from package1 import module1
    from package1.module2 import function1
    from package2 import class1
    from package2.subpackage1.module5 import funtion2

Relative imports are to be preferred

Relative Imports
=================

Import from same directory use 1 dot ., import from parent directory use 2 dots .., import from
grandparent directory use 3 dots ..., and so on.

To import a class from the current directory use::

    from . import class

Where the single dot is the current directory.

Thanks to `Real Python- Absolute vs Relative Imports` <https://realpython
.com/absolute-vs-relative-python-imports/>`_

List Comprehensions
********************

Syntax:

::

    [expression for target1 in iterable1 if condition1
                *for target2 in iterable2 if condition2 ...
                *for targetN in iterableN if conditionN ...]