Get your package started by converting scripts you have already written. You'll create a simple package which you can use on your own computer.

Starting a package

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Modules, packages and subpackages

# Open the text file
with open('alice.txt') as file:
    text = file.read()

n = 0
for word in text.split():
    # Count the number of times the words in the list appear
    if word.lower() in ['cat', 'cats']:
        n += 1

print('Lewis Carroll uses the word "cat" {} times'.format(n))


def count_words(filepath, words_list):
    # Open the text file
    with open(filepath) as file:
        text = file.read()
    
    n = 0
    for word in text.split():
        # Count the number of times the words in the list appear
        if word.lower() in words_list:
            n += 1
    return n


From script to package

def count_words(filepath, words_list):
    # Open the text file
    with open(filepath) as file:
        text = file.read()
    # Count number of times these words appear
    n = 0
    for word in text.split():
        if word.lower() in words_list:
            n += 1
    return n


from textanalysis.textanalysis import count_words

# Count the number of positive words
nb_positive_words = ____(____, [____, ____])

# Count the number of negative words
nb_negative_words = ____(____, ____)

print("{} positive words.".format(nb_positive_words))
print("{} negative words.".format(nb_negative_words))


from textanalysis.textanalysis import count_words

# Count the number of positive words
nb_positive_words = count_words('hotel-reviews.txt', ['good', 'great'])

# Count the number of negative words
nb_negative_words = count_words('hotel-reviews.txt', ['bad', 'awful'])

print("{} positive words.".format(nb_positive_words))
print("{} negative words.".format(nb_negative_words))


Putting your package to work

Documentation

INCHES_PER_FOOT = 12.0  # 12 inches in a foot
INCHES_PER_YARD = INCHES_PER_FOOT * 3.0  # 3 feet in a yard

UNITS = ("in", "ft", "yd")


def inches_to_feet(x, reverse=False):
    if reverse:
        return x * INCHES_PER_FOOT
    else:
        return x / INCHES_PER_FOOT


INCHES_PER_FOOT = 12.0  # 12 inches in a foot
INCHES_PER_YARD = INCHES_PER_FOOT * 3.0  # 3 feet in a yard

UNITS = ("in", "ft", "yd")

def inches_to_feet(x, reverse=False):
    """

    Parameters
    ----------
    x :

    reverse :
         (Default value = False)

    Returns
    -------

    """
    if reverse:
        return x * INCHES_PER_FOOT
    else:
        return x / INCHES_PER_FOOT


# Run the following command in the console
# pyment -w -o numpydoc impyrial/length/core.py

Writing function documentation with pyment

INCHES_PER_FOOT = 12.0  # 12 inches in a foot
INCHES_PER_YARD = INCHES_PER_FOOT * 3.0  # 3 feet in a yard

UNITS = ("in", "ft", "yd")


def inches_to_feet(x, reverse=False):
    """

    Parameters
    ----------
    x :

    reverse :
         (Default value = False)

    Returns
    -------

    """
    if reverse:
        return x * INCHES_PER_FOOT
    else:
        return x / INCHES_PER_FOOT


INCHES_PER_FOOT = 12.0  # 12 inches in a foot
INCHES_PER_YARD = INCHES_PER_FOOT * 3.0  # 3 feet in a yard

UNITS = ("in", "ft", "yd")


def inches_to_feet(x, reverse=False):
    """Convert lengths between inches and feet.

    Parameters
    ----------
    x : numpy.ndarray
        Lengths in feet.
    reverse : bool, optional
        If true this function converts from feet to inches 
        instead of the default behavior of inches to feet. 
        (Default value = False)

    Returns
    -------
    numpy.ndarray
    """
    if reverse:
        return x * INCHES_PER_FOOT
    else:
        return x / INCHES_PER_FOOT


Writing function documentation with pyment II

"""
impyrial
========
A package for converting between imperial measurements of length and weight.
"""


"""
impyrial.length
===============
Length conversion between imperial units.
"""


"""Conversions between inches and larger imperial length units"""
INCHES_PER_FOOT = 12.0  # 12 inches in a foot
INCHES_PER_YARD = INCHES_PER_FOOT * 3.0  # 3 feet in a yard

UNITS = ("in", "ft", "yd")


def inches_to_feet(x, reverse=False):
    """Convert lengths between inches and feet.

    Parameters
    ----------
    x : numpy.ndarray
        Lengths in feet.
    reverse : bool, optional
        If true this function converts from feet to inches 
        instead of the default behavior of inches to feet. 
        (Default value = False)

    Returns
    -------
    numpy.ndarray
    """
    if reverse:
        return x * INCHES_PER_FOOT
    else:
        return x / INCHES_PER_FOOT


Package and module documentation

Structuring imports

from ____ import ____

result = convert_unit(10, 'in', 'yd')
print(result)


"""User-facing functions."""
from ____ import (
    ____,
    ____,
    ____
)


def convert_unit(x, from_unit, to_unit):
    """Convert from one length unit to another.

    Parameters
    ----------
    x : array_like
        Lengths to convert.
    from_unit : {'in', 'ft', 'yd'}
        Unit of the input lengths `x`
    to_unit : {'in', 'ft', 'yd'}
        Unit of the returned lengths

    Returns
    -------
    ndarray
        An array of converted lengths with the same shape as `x`. If `x` is a
        0-d array, then a scalar is returned.
    """
    # Convert length to inches
    if from_unit == "in":
        inches = x
    elif from_unit == "ft":
        inches = inches_to_feet(x, reverse=True)
    elif from_unit == "yd":
        inches = inches_to_yards(x, reverse=True)

    # Convert inches to desired units
    if to_unit == "in":
        value = inches
    elif to_unit == "ft":
        value = inches_to_feet(inches)
    elif to_unit == "yd":
        value = inches_to_yards(inches)

    return value


from impyrial.length.api import convert_unit

result = convert_unit(10, 'in', 'yd')
print(result)


"""User-facing functions."""
from impyrial.length.core import (
    UNITS,
    inches_to_feet,
    inches_to_yards
)


def convert_unit(x, from_unit, to_unit):
    """Convert from one length unit to another.

    Parameters
    ----------
    x : array_like
        Lengths to convert.
    from_unit : {'in', 'ft', 'yd'}
        Unit of the input lengths `x`
    to_unit : {'in', 'ft', 'yd'}
        Unit of the returned lengths

    Returns
    -------
    ndarray
        An array of converted lengths with the same shape as `x`. If `x` is a
        0-d array, then a scalar is returned.
    """
    # Convert length to inches
    if from_unit == "in":
        inches = x
    elif from_unit == "ft":
        inches = inches_to_feet(x, reverse=True)
    elif from_unit == "yd":
        inches = inches_to_yards(x, reverse=True)

    # Convert inches to desired units
    if to_unit == "in":
        value = inches
    elif to_unit == "ft":
        value = inches_to_feet(inches)
    elif to_unit == "yd":
        value = inches_to_yards(inches)

    return value


Sibling imports

from impyrial.length.api import convert_unit

# Make sure unit checking is working by trying examples
print('The following line should run:')
result1 = convert_unit(10, 'in', 'yd')
print(result1)

print('The following line should cause an error:')
result2 = convert_unit(10, 'lb', 'yd')
print(result2)


"""User-facing functions."""
# Import the check_units function
____
from impyrial.length.core import (
    UNITS,
    inches_to_feet,
    inches_to_yards,
)


def convert_unit(x, from_unit, to_unit):
    """Convert from one length unit to another.

    Parameters
    ----------
    x : array_like
        Lengths to convert.
    from_unit : {'in', 'ft', 'yd'}
        Unit of the input lengths `x`
    to_unit : {'in', 'ft', 'yd'}
        Unit of the returned lengths

    Returns
    -------
    ndarray
        An array of converted lengths with the same shape as `x`. If `x` is a
        0-d array, then a scalar is returned.
    """
    # Check if units are valid length units
    check_units(from_unit, to_unit, UNITS)
    
    # convert length to inches
    if from_unit == "in":
        inches = x
    elif from_unit == "ft":
        inches = inches_to_feet(x, reverse=True)
    elif from_unit == "yd":
        inches = inches_to_yards(x, reverse=True)

    # Convert inches to desired units
    if to_unit == "in":
        value = inches
    elif to_unit == "ft":
        value = inches_to_feet(inches)
    elif to_unit == "yd":
        value = inches_to_yards(inches)

    return value


"""User-facing functions."""
# Import the check_units function
from impyrial.utils import check_units
from impyrial.length.core import (
    UNITS,
    inches_to_feet,
    inches_to_yards,
)


def convert_unit(x, from_unit, to_unit):
    """Convert from one length unit to another.

    Parameters
    ----------
    x : array_like
        Lengths to convert.
    from_unit : {'in', 'ft', 'yd'}
        Unit of the input lengths `x`
    to_unit : {'in', 'ft', 'yd'}
        Unit of the returned lengths

    Returns
    -------
    ndarray
        An array of converted lengths with the same shape as `x`. If `x` is a
        0-d array, then a scalar is returned.
    """
    # Check if units are valid length units
    check_units(from_unit, to_unit, UNITS)
    
    # Convert length to inches
    if from_unit == "in":
        inches = x
    elif from_unit == "ft":
        inches = inches_to_feet(x, reverse=True)
    elif from_unit == "yd":
        inches = inches_to_yards(x, reverse=True)

    # Convert inches to desired units
    if to_unit == "in":
        value = inches
    elif to_unit == "ft":
        value = inches_to_feet(inches)
    elif to_unit == "yd":
        value = inches_to_yards(inches)

    return value


Importing from parents

# This is the __init__.py file for the impyrial/length subpackage

# Import the convert_unit function from the api.py module
____


# This is the top level __init__.py file

# Import the length subpackage
____


import impyrial

result = impyrial.length.convert_unit(10, 'in', 'yd')
print(result)


# This is the __init__.py file for the impyrial/length subpackage

# Import the convert_unit function from the api.py module
from .api import convert_unit


# This is the top level __init__.py file

# Import the length subpackage
from . import length


Exposing functions to users

From Loose Code to Local Package

Make your package installable for yourself and others. In this chapter, you'll learn to deal with dependencies,  write READMEs, and include licenses. You'll also complete all the steps to publish your package on PyPI—the main home of Python packages.

Installing your own package

Adding the setup script

Installing your package locally

Utilizing editable installs

Dealing with dependencies

User dependencies

Development dependencies

Including licences and writing READMEs

Writing a README

MANIFEST - Including extra files with your package

Publishing your package

Building a distribution

Uploading distributions

Install Your Package from Anywhere

Bring your package up to a professional standard. Discover how to use pytest to guard against errors, tox to test if your package functions with multiple versions of Python, and flake8 to maintain great code style.

Testing your package

Creating the test directory

Writing some basic tests

Running your tests

Testing your package with different environments

Setting up tox

Running tox

Keeping your package stylish

Appropriate style filtering

Using flake8 to tidy up a file

Ignoring specific errors

Configuring flake8

Increasing Your Package Quality

Create your packages more quickly. In this final chapter, you’ll learn how to use cookiecutter to generate all the supporting files your package needs, Makefiles to simplify releasing new versions, and be introduced to the last few files your package needs to attract users and contributors.

Faster package development with templates

Using package templates

Version numbers and history

CONTRIBUTING.md

History file

Tracking version number with bumpversion

Makefiles and classifiers

PyPI classifiers

Using makefiles

Wrap-up

Rapid Package Development

Do you find yourself copying and pasting the same code between files, wishing it was easier to reuse and share your awesome snippets? Wrapping your code into Python packages can help! In this course, you’ll learn about package structure and the extra files needed to turn loose code into convenient packages. You'll also learn about import structure, documentation, and how to maintain code style using flake8. You’ll then speed up your package development by building templates, using cookiecutter to create package skeletons. Finally, you'll learn how to use setuptools and twine to build and publish your packages to PyPI—the world stage for Python packages.

Introduction to Shell

Writing Functions in Python

Learn about package structure, import structure, documentation, and how to maintain code style then build templates and use setup tools to publish them.

Developing Python Packages

Learn to create your own Python packages to make your code easier to use and share with others.

Modules, packages and subpackages

Interaktive praktische Übung