=========
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(, )
>>> 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.