pyalgos

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pyalgos is a package for implementing various algorithms:

  • Sorting
    • Insertion Sort
    • Selection Sort
    • Merge Sort

Features

  • Supported on Python 2.7 and Python 3.3+.

Quickstart

Install using pip:

pip install pyalgos

Guide

Installation

pyalgos requires Python 2.7 or 3.3+.

To install from PyPI:

pip install pyalgos

You can also install pyalgos with all the latest changes:

$ git clone git@github.com:bharadwajyarlagadda/pyalgos.git
$ cd pyalgos
$ python setup.py install

User’s Guide

Sorting

Insertion Sort

A simple sorting algorithm that builds the final sorted list of items - one item at a time. It can be less efficient on larger lists.

  • Best Case: Input is already sorted out. This takes only O(n) running time. For ex, [1, 2, 3, 4, 5] - in this case it takes only linear time to sort out the items.
  • Average/Worst Cases: In both the cases, it takes O(pow(n, 2)) running time to sort out the items. In both these cases, the items in the list are either in a reverse order (or) zig-zag order.

You can use Insertion Sort from pyalgos for both list of integers and list of strings.

from pyalgos.sorting import insertion

numbers_sorted = insertion([3, 4, 2, 7, 5, 1])
alphabets_sorted = insertion(['a', 'z', 'y', 'b', 'w'])

assert numbers_sorted == [1, 2, 3, 4, 5, 7]
assert alphabets_sorted == ['a', 'b', 'w', 'y', 'z']

Note

You can provide either list/tuple of values.

Selection Sort

A sorting algorithm that build the final sorted list of items. It is inefficient on larger lists.

  • Best/Average/Worst Cases: In all these cases, the running time is O(pow(n, 2)).

You can use Selection Sort from pyalgos for both list of integers and list of strings.

from pyalgos.sorting import selection

numbers_sorted = selection([3, 4, 2, 7, 5, 1])
alphabets_sorted = selection(['a', 'z', 'y', 'b', 'w'])

assert numbers_sorted == [1, 2, 3, 4, 5, 7]
assert alphabets_sorted == ['a', 'b', 'w', 'y', 'z']

Note

You can provide either list/tuple of values.

Merge Sort

A sorting algorithm that build the final sorted list of items. It is a divide and conquer algorithm.

  • Best/Average/Worst Cases: In all these cases, the running time is O(n * log(n)).

You can use Merge Sort from pyalgos for both list of integers and list of strings.

from pyalgos.sorting import merge

numbers_sorted = merge([3, 4, 2, 7, 5, 1])
alphabets_sorted = merge(['a', 'z', 'y', 'b', 'w'])

assert numbers_sorted == [1, 2, 3, 4, 5, 7]
assert alphabets_sorted == ['a', 'b', 'w', 'y', 'z']

Note

You can provide either list/tuple of values.

API Reference

Sorting

pyalgos.sorting.insertion(elements)[source]

Returns the sorted values using insertion sort algorithm.

The best case is when the input is an array that is already sorted. In this case, insertion sort has a linear running time O(n).

The worst case is when the input is an array sorted in reverse order. In this case, insertion sort has a quadratic running time O(pow(n,2)).

Parameters:elements (list/tuple) – A list/tuple of values provided by the user.
Returns:A list/tuple of elements sorted in ascending order.
Return type:list/tuple

New in version 0.1.0.

Changed in version 0.1.1: Added validation for checking whether every element in the list is a string (when strings are provided in the list).

Changed in version 0.1.2: Added support for tuples. Now the user can also provide a tuple of values.

Changed in version 0.2.0: insertion() can now return the list when the size of list is less than or equal to 1.

pyalgos.sorting.selection(elements)[source]

Returns the sorted values using selection sort algorithm.

Selection sort has O(pow(n, 2)) time complexity in all the three cases (Best, Average and Worst).

Parameters:elements (list/tuple) – A list/tuple of values provided by the user.
Returns:A list/tuple of elements sorted in ascending order.
Return type:list/tuple

New in version 0.1.0.

Changed in version 0.1.1: Added validation for checking whether every element in the list is a string (when strings are provided in the list).

Changed in version 0.1.2: Added support for tuples. Now the user can also provide a tuple of values.

Changed in version 0.2.0: selection() can now return the list when the size of list is less than or equal to 1.

pyalgos.sorting.merge(elements)[source]

Returns the sorted values using merge sort algorithm.

The time complexity will always be O(n * log(n)).

Parameters:elements (list/tuple) – A list/tuple of values provided by the user.
Returns:A list/tuple of elements sorted in ascending order.
Return type:list/tuple

New in version 0.2.0.

Project Info

License

MIT License

Copyright (c) 2016 Bharadwaj Yarlagadda

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Versioning

This project follows Semantic Versioning.

It is recommended to only use or import objects from the main module, pyalgos.

Changelog

v0.2.0

  • Added merge() method for implementing merge sort algorithm.
  • insertion()/selection() can now just return the list when the size of list is less than or equal to 1.

v0.1.2

  • Added support for tuple of values in both insertion() and selection() sorting methods.

v0.1.1

  • Added validation for checking whether all the elements in a given list are strings or not in both insertion() and selection() sorting methods.

v0.1.0

  • First release.
  • Added insertion() method for implementing insertion sort algorithm.
  • Added selection() method for implementing selection sort algorithm.

Contributing

Contributions are welcome, and they are greatly appreciated! Every little bit helps, and credit will always be given.

You can contribute in many ways:

Types of Contributions

Report Bugs

Report bugs at https://github.com/bharadwajyarlagadda/pyalgos.

If you are reporting a bug, please include:

  • Your operating system name and version.
  • Any details about your local setup that might be helpful in troubleshooting.
  • Detailed steps to reproduce the bug.
Fix Bugs

Look through the GitHub issues for bugs. Anything tagged with “bug” is open to whoever wants to implement it.

Implement Features

Look through the GitHub issues for features. Anything tagged with “enhancement” or “help wanted” is open to whoever wants to implement it.

Write Documentation

pyalgos could always use more documentation, whether as part of the official pyalgos docs, in docstrings, or even on the web in blog posts, articles, and such.

Submit Feedback

The best way to send feedback is to file an issue at https://github.com/bharadwajyarlagadda/pyalgos.

If you are proposing a feature:

  • Explain in detail how it would work.
  • Keep the scope as narrow as possible, to make it easier to implement.
  • Remember that this is a volunteer-driven project, and that contributions are welcome :)

Get Started!

Ready to contribute? Here’s how to set up pyalgos for local development.

  1. Fork the pyalgos repo on GitHub.

  2. Pull your fork locally:

    $ git clone git@github.com:<username>/pyalgos.git

  3. Install your local copy into a virtualenv. Assuming you have virtualenv installed, this is how you set up your fork for local development:

    $ cd pyalgos
$ pip install -r requirements-dev.txt

  4. Create a branch for local development:

    $ git checkout -b name-of-your-bugfix-or-feature

    Now you can make your changes locally.

  5. When you’re done making changes, check that your changes pass linting and all unit tests by testing with tox across all supported Python versions:

    $ invoke tox

  6. Add yourself to AUTHORS.rst.

  7. Commit your changes and push your branch to GitHub:

    $ git add .
$ git commit -m "Detailed description of your changes."
$ git push origin name-of-your-bugfix-or-feature

  8. Submit a pull request through the GitHub website.

Pull Request Guidelines

Before you submit a pull request, check that it meets these guidelines:

  1. The pull request should include tests.
  2. If the pull request adds functionality, the docs should be updated. Put your new functionality into a function with a docstring, and add the feature to the README.rst.
  3. The pull request should work for Python 2.7, 3.4, and 3.5. Check https://travis-ci.org/bharadwajyarlagadda/pyalgos/pull_requests and make sure that the tests pass for all supported Python versions.

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