=========
FlashText
=========
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This module can be used to replace keywords in sentences or extract keywords from sentences. It is based on the `FlashText algorithm <https://arxiv.org/abs/1711.00046>`_.
Installation
------------
::
$ pip install flashtext
API doc
-------
Documentation can be found at `FlashText Read the Docs
<http://flashtext.readthedocs.io/>`_.
Usage
-----
Extract keywords
>>> from flashtext import KeywordProcessor
>>> keyword_processor = KeywordProcessor()
>>> # keyword_processor.add_keyword(<unclean name>, <standardised name>)
>>> keyword_processor.add_keyword('Big Apple', 'New York')
>>> keyword_processor.add_keyword('Bay Area')
>>> keywords_found = keyword_processor.extract_keywords('I love Big Apple and Bay Area.')
>>> keywords_found
>>> # ['New York', 'Bay Area']
Replace keywords
>>> keyword_processor.add_keyword('New Delhi', 'NCR region')
>>> new_sentence = keyword_processor.replace_keywords('I love Big Apple and new delhi.')
>>> new_sentence
>>> # 'I love New York and NCR region.'
Case Sensitive example
>>> from flashtext import KeywordProcessor
>>> keyword_processor = KeywordProcessor(case_sensitive=True)
>>> keyword_processor.add_keyword('Big Apple', 'New York')
>>> keyword_processor.add_keyword('Bay Area')
>>> keywords_found = keyword_processor.extract_keywords('I love big Apple and Bay Area.')
>>> keywords_found
>>> # ['Bay Area']
Span of keywords extracted
>>> from flashtext import KeywordProcessor
>>> keyword_processor = KeywordProcessor()
>>> keyword_processor.add_keyword('Big Apple', 'New York')
>>> keyword_processor.add_keyword('Bay Area')
>>> keywords_found = keyword_processor.extract_keywords('I love big Apple and Bay Area.', span_info=True)
>>> keywords_found
>>> # [('New York', 7, 16), ('Bay Area', 21, 29)]
Get Extra information with keywords extracted
>>> from flashtext import KeywordProcessor
>>> kp = KeywordProcessor()
>>> kp.add_keyword('Taj Mahal', ('Monument', 'Taj Mahal'))
>>> kp.add_keyword('Delhi', ('Location', 'Delhi'))
>>> kp.extract_keywords('Taj Mahal is in Delhi.')
>>> # [('Monument', 'Taj Mahal'), ('Location', 'Delhi')]
>>> # NOTE: replace_keywords feature won't work with this.
No clean name for Keywords
>>> from flashtext import KeywordProcessor
>>> keyword_processor = KeywordProcessor()
>>> keyword_processor.add_keyword('Big Apple')
>>> keyword_processor.add_keyword('Bay Area')
>>> keywords_found = keyword_processor.extract_keywords('I love big Apple and Bay Area.')
>>> keywords_found
>>> # ['Big Apple', 'Bay Area']
Add Multiple Keywords simultaneously
>>> from flashtext import KeywordProcessor
>>> keyword_processor = KeywordProcessor()
>>> keyword_dict = {
>>> "java": ["java_2e", "java programing"],
>>> "product management": ["PM", "product manager"]
>>> }
>>> # {'clean_name': ['list of unclean names']}
>>> keyword_processor.add_keywords_from_dict(keyword_dict)
>>> # Or add keywords from a list:
>>> keyword_processor.add_keywords_from_list(["java", "python"])
>>> keyword_processor.extract_keywords('I am a product manager for a java_2e platform')
>>> # output ['product management', 'java']
To Remove keywords
>>> from flashtext import KeywordProcessor
>>> keyword_processor = KeywordProcessor()
>>> keyword_dict = {
>>> "java": ["java_2e", "java programing"],
>>> "product management": ["PM", "product manager"]
>>> }
>>> keyword_processor.add_keywords_from_dict(keyword_dict)
>>> print(keyword_processor.extract_keywords('I am a product manager for a java_2e platform'))
>>> # output ['product management', 'java']
>>> keyword_processor.remove_keyword('java_2e')
>>> # you can also remove keywords from a list/ dictionary
>>> keyword_processor.remove_keywords_from_dict({"product management": ["PM"]})
>>> keyword_processor.remove_keywords_from_list(["java programing"])
>>> keyword_processor.extract_keywords('I am a product manager for a java_2e platform')
>>> # output ['product management']
To check Number of terms in KeywordProcessor
>>> from flashtext import KeywordProcessor
>>> keyword_processor = KeywordProcessor()
>>> keyword_dict = {
>>> "java": ["java_2e", "java programing"],
>>> "product management": ["PM", "product manager"]
>>> }
>>> keyword_processor.add_keywords_from_dict(keyword_dict)
>>> print(len(keyword_processor))
>>> # output 4
To check if term is present in KeywordProcessor
>>> from flashtext import KeywordProcessor
>>> keyword_processor = KeywordProcessor()
>>> keyword_processor.add_keyword('j2ee', 'Java')
>>> 'j2ee' in keyword_processor
>>> # output: True
>>> keyword_processor.get_keyword('j2ee')
>>> # output: Java
>>> keyword_processor['colour'] = 'color'
>>> keyword_processor['colour']
>>> # output: color
Get all keywords in dictionary
>>> from flashtext import KeywordProcessor
>>> keyword_processor = KeywordProcessor()
>>> keyword_processor.add_keyword('j2ee', 'Java')
>>> keyword_processor.add_keyword('colour', 'color')
>>> keyword_processor.get_all_keywords()
>>> # output: {'colour': 'color', 'j2ee': 'Java'}
For detecting Word Boundary currently any character other than this `\\w` `[A-Za-z0-9_]` is considered a word boundary.
To set or add characters as part of word characters
>>> from flashtext import KeywordProcessor
>>> keyword_processor = KeywordProcessor()
>>> keyword_processor.add_keyword('Big Apple')
>>> print(keyword_processor.extract_keywords('I love Big Apple/Bay Area.'))
>>> # ['Big Apple']
>>> keyword_processor.add_non_word_boundary('/')
>>> print(keyword_processor.extract_keywords('I love Big Apple/Bay Area.'))
>>> # []
Test
----
::
$ git clone https://github.com/vi3k6i5/flashtext
$ cd flashtext
$ pip install pytest
$ python setup.py test
Build Docs
----------
::
$ git clone https://github.com/vi3k6i5/flashtext
$ cd flashtext/docs
$ pip install sphinx
$ make html
$ # open _build/html/index.html in browser to view it locally
Why not Regex?
--------------
It's a custom algorithm based on `Aho-Corasick algorithm
<https://en.wikipedia.org/wiki/Aho%E2%80%93Corasick_algorithm>`_ and `Trie Dictionary
<https://en.wikipedia.org/wiki/Trie Dictionary>`_.
.. image:: https://github.com/vi3k6i5/flashtext/raw/master/benchmark.png
:target: https://twitter.com/RadimRehurek/status/904989624589803520
:alt: Benchmark
Time taken by FlashText to find terms in comparison to Regex.
.. image:: https://thepracticaldev.s3.amazonaws.com/i/xruf50n6z1r37ti8rd89.png
Time taken by FlashText to replace terms in comparison to Regex.
.. image:: https://thepracticaldev.s3.amazonaws.com/i/k44ghwp8o712dm58debj.png
Link to code for benchmarking the `Find Feature <https://gist.github.com/vi3k6i5/604eefd92866d081cfa19f862224e4a0>`_ and `Replace Feature <https://gist.github.com/vi3k6i5/dc3335ee46ab9f650b19885e8ade6c7a>`_.
The idea for this library came from the following `StackOverflow question
<https://stackoverflow.com/questions/44178449/regex-replace-is-taking-time-for-millions-of-documents-how-to-make-it-faster>`_.
Citation
----------
The original paper published on `FlashText algorithm <https://arxiv.org/abs/1711.00046>`_.
::
@ARTICLE{2017arXiv171100046S,
author = {{Singh}, V.},
title = "{Replace or Retrieve Keywords In Documents at Scale}",
journal = {ArXiv e-prints},
archivePrefix = "arXiv",
eprint = {1711.00046},
primaryClass = "cs.DS",
keywords = {Computer Science - Data Structures and Algorithms},
year = 2017,
month = oct,
adsurl = {http://adsabs.harvard.edu/abs/2017arXiv171100046S},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
The article published on `Medium freeCodeCamp <https://medium.freecodecamp.org/regex-was-taking-5-days-flashtext-does-it-in-15-minutes-55f04411025f>`_.
Contribute
----------
- Issue Tracker: https://github.com/vi3k6i5/flashtext/issues
- Source Code: https://github.com/vi3k6i5/flashtext/
License
-------
The project is licensed under the MIT license.