User-Defined-Regular-Expressions

Using Horspool Algorithm

Horspool String Searching Algorithm

This is a Python implementation of the Horspool string searching algorithm. The Horspool algorithm is used to find occurrences of a pattern string within a given text string. The implementation includes variations of the algorithm to handle different pattern cases, such as wildcard characters and anchor characters.

Usage

download the code files.
Modify the text and pattern input files as needed. You can replace the contents of the textN.txt and patternN.txt files with your own text and pattern strings.
Run the main.py script to perform the string search and generate output files.

python assignment_01.py compiler ask to enter N value as your file name. for example if you need run text5.txt and pattern5.txt set. Then you should input 5.
The output files, named outputN.txt, will be generated, showing the positions where the pattern was found in the text.

Variations

The algorithm includes different variations to handle various pattern cases:

horspool(text, pattern, text_file): Basic Horspool algorithm to search for exact pattern matches.
horspool_dot(text, pattern, text_file): Horspool algorithm with support for the . wildcard character.
horspool_quest(text, pattern, text_file): Horspool algorithm to handle patterns containing ? characters.
horspool_begg(text, pattern, text_file): Horspool algorithm to handle patterns anchored at the beginning.
horspool_end(text, pattern, text_file): Horspool algorithm to handle patterns anchored at the end.

Input Files

textN.txt: Replace N with the specific input number. Contains the text in which the pattern is searched.
patternN.txt: Replace N with the specific input number. Contains the pattern string to be searched.

Output