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daachorse is a fast implementation of the Aho-Corasick algorithm using the compact double-array data structure.This is a Python wrapper.

Run the following command:

$ pip install daachorse

You need to install the Rust compiler followingthe documentation beforehand.daachorse usespyproject.toml, so you also need to upgrade pip to version 19 or later.

$ pip install --upgrade pip

After setting up the environment, you can install daachorse as follows:

$ pip install git+https://github.com/daac-tools/python-daachorse

Daachorse contains some search options,ranging from basic matching with the Aho-Corasick algorithm to trickier matching.All of them will run very fast based on the double-array data structure andcan be easily plugged into your application as shown below.

To search for all occurrences of registered patternsthat allow for positional overlap in the input text,usefind_overlapping(). When you instantiate a new automaton,unique identifiers are assigned to each pattern in the input order.The match result has the character positions of the occurrence and its identifier.

>>importdaachorse>>patterns= ['bcd','ab','a']>>pma=daachorse.Automaton(patterns)>>pma.find_overlapping('abcd')[(0,1,2), (0,2,1), (1,4,0)]

If you do not want to allow positional overlap, usefind() instead.It performs the search on the Aho-Corasick automatonand reports patterns first found in each iteration.

>>importdaachorse>>patterns= ['bcd','ab','a']>>pma=daachorse.Automaton(patterns)>>pma.find('abcd')[(0,1,2), (1,4,0)]

If you want to search for the longest pattern without positional overlap in each iteration,useMATCH_KIND_LEFTMOST_LONGEST in the construction.

>>importdaachorse>>patterns= ['ab','a','abcd']>>pma=daachorse.Automaton(patterns,daachorse.MATCH_KIND_LEFTMOST_LONGEST)>>pma.find('abcd')[(0,4,2)]

If you want to find the the earliest registered patternamong ones starting from the search position,useMATCH_KIND_LEFTMOST_FIRST.

This is so-calledthe leftmost first match, a bit tricky search option.For example, in the following code,ab is reported because it is the earliest registered one.

>>importdaachorse>>patterns= ['ab','a','abcd']>>pma=daachorse.Automaton(patterns,daachorse.MATCH_KIND_LEFTMOST_FIRST)>>pma.find('abcd')[(0,2,0)]

Licensed under either of

• Apache License, Version 2.0(LICENSE-APACHE orhttp://www.apache.org/licenses/LICENSE-2.0)
• MIT license(LICENSE-MIT orhttp://opensource.org/licenses/MIT)

at your option.