Metadata-Version: 1.2
Name: ahocorapy
Version: 1.3.0
Summary: ahocorapy - Pure python ahocorasick implementation
Home-page: https://github.com/abusix/ahocorapy
Author: abusix
Author-email: fp@abusix.com
License: MIT
Project-URL: Source, https://github.com/abusix/ahocorapy
Project-URL: Company, https://www.abusix.com/
Description-Content-Type: UNKNOWN
Description: |Build Status| |Test Coverage| |PyPi Version| |PyPi License| |PyPi
        Versions| |PyPi Wheel|
        
        ahocorapy - Fast Many-Keyword Search in Pure Python
        ===================================================
        
        ahocorapy is a pure python implementation of the Aho-Corasick Algorithm.
        Given a list of keywords one can check if at least one of the keywords
        exist in a given text in linear time.
        
        Comparison:
        -----------
        
        Why another Aho-Corasick implementation?
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        
        We started working on this in the beginning of 2016. Our requirements
        included unicode support combined with python2.7. That was impossible
        with C-extension based libraries (like
        `pyahocorasick <https://github.com/WojciechMula/pyahocorasick/>`__).
        Pure python libraries were very slow or unusable due to memory
        explosion. Since then another pure python library was released
        `py-aho-corasick <https://github.com/JanFan/py-aho-corasick>`__. The
        repository also contains some discussion about different
        implementations. There is also
        `acora <https://github.com/scoder/acora>`__, but it includes the note
        ('current construction algorithm is not suitable for really large sets
        of keywords') which really was the case the last time I tested, because
        RAM ran out quickly.
        
        Differences
        ~~~~~~~~~~~
        
        -  Compared to
           `pyahocorasick <https://github.com/WojciechMula/pyahocorasick/>`__
           our library supports unicode in python 2.7 just like
           `py-aho-corasick <https://github.com/JanFan/py-aho-corasick>`__. We
           don't use any C-Extension so the library is not platform dependant.
        
        -  We don't look for multiple results, we are okay with finding only
           one. We might extend this in the future. For our use cases that was
           sufficient and helps with performance.
        
        -  On top of the standard Aho-Corasick longest suffix search, we also
           perform a shortcutting routine in the end, so that our lookup is fast
           while, the setup takes longer. During set up we go through the states
           and directly add transitions that are "offered" by the longest suffix
           or their longest suffixes. This leads to faster lookup times, because
           in the end we only have to follow simple transitions and don't have
           to perform any additional suffix lookup. It also leads to a bigger
           memory footprint, because the number of transitions is higher,
           because they are all included explicitely and not implicitely hidden
           by suffix pointers.
        
        -  We added a small tool that helps you visualize the resulting graph.
           This may help understanding the algorithm, if you'd like. See below.
        
        Performance
        ~~~~~~~~~~~
        
        I compared the two libraries mentioned above with ahocorapy. We used
        50,000 keywords long list and an input text of 34,199 characters. In the
        text only one keyword of the list is contained. The setup process was
        run once per library and the search process was run 100 times. The
        following results are in seconds (not averaged for the lookup).
        
        You can perform this test yourself using
        ``python tests/ahocorapy_performance_test.py``. (Except for the
        pyahocorasick\_py results. These were taken by importing the pure python
        version of the code of
        `pyahocorasick <https://github.com/WojciechMula/pyahocorasick/>`__. It's
        not available through pypi as stated in the code.
        
        These are the results:
        
        ::
        
            ----------ahocorapy----------
            setup_ahocorapy: 2.407656837000104
            search_ahocorapy: 0.918015885999921
            ----------pyahocorasick----------
            setup_pyahocorasick: 0.09675870799947006
            search_pyahocorasick: 0.06381417899865482
            ----------pyahocorasick python----------
            setup_pyahocorasick_py: 0.5029343919995881
            search_pyahocorasick_py: 1.6796333189995494
            ----------py_aho_corasick----------
            setup_py_aho_corasick: 1.8584364769994863
            search_py_aho_corasick: 13.236364944999877
        
        As expected the C-Extension shatters the pure python implementations.
        Even though there is probably still room for optimization in ahocorapy
        we are not going to get to the mark that pyahocorasick sets. Our lookups
        are faster than py\_aho\_corasick though, but that can also vary
        depending on how the data is structured (both keywords and input text).
        
        Basic Usage:
        ------------
        
        Creation of the Search Tree
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~
        
        .. code:: python
        
            kwtree = KeywordTree(case_insensitive=True)
            kwtree.add('malaga')
            kwtree.add('lacrosse')
            kwtree.add('mallorca')
            kwtree.add('mallorca bella')
            kwtree.finalize()
        
        Searching
        ~~~~~~~~~
        
        .. code:: python
        
            result = kwtree.search('My favorite islands are malaga and sylt.')
            print result
        
        Prints :
        
        .. code:: python
        
            ('malaga', 24)
        
        The search method always returns the first keyword found, or None if
        there is none.
        
        .. code:: python
        
            result = kwtree.search('crossing on mallorca bella')
            print result
        
        Prints :
        
        .. code:: python
        
            ('mallorca', 12)
        
        and not 'mallorca bella'. Since 'mallorca' is a strict prefix of it.
        
        Drawing Graph
        -------------
        
        You can print the underlying graph with the Visualizer class. This
        feature requires a working pygraphviz library installed.
        
        .. code:: python
        
            from ahocorapy_visualizer.visualizer import Visualizer
            visualizer = Visualizer()
            visualizer.draw('readme_example.png', kwtree)
        
        The resulting .png of the graph looks like this:
        
        .. figure:: img/readme_example.png
           :alt: Keyword Tree
        
           graph for kwtree
        
        .. |Build Status| image:: https://img.shields.io/travis/abusix/ahocorapy/master.svg
           :target: https://travis-ci.org/abusix/ahocorapy
        .. |Test Coverage| image:: https://img.shields.io/coveralls/github/abusix/ahocorapy/master.svg
           :target: https://pypi.python.org/pypi/ahocorapy
        .. |PyPi Version| image:: https://img.shields.io/pypi/v/ahocorapy.svg
           :target: https://pypi.python.org/pypi/ahocorapy
        .. |PyPi License| image:: https://img.shields.io/pypi/l/ahocorapy.svg
           :target: https://pypi.python.org/pypi/ahocorapy
        .. |PyPi Versions| image:: https://img.shields.io/pypi/pyversions/ahocorapy.svg
           :target: https://pypi.python.org/pypi/ahocorapy
        .. |PyPi Wheel| image:: https://img.shields.io/pypi/wheel/ahocorapy.svg
           :target: https://pypi.python.org/pypi/ahocorapy
        
Keywords: keyword,search,purepython,aho-corasick,ahocorasick,abusix
Platform: UNKNOWN
Classifier: Development Status :: 5 - Production/Stable
Classifier: Intended Audience :: Developers
Classifier: Topic :: Software Development :: Libraries :: Python Modules
Classifier: License :: OSI Approved :: MIT License
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.3
Classifier: Programming Language :: Python :: 3.4
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Requires-Python: >=2.7
