Simple search system that includes inverted index builder and boolean query processor for information retrieval.

This program uses Reuters-21578 Dataset. Please place the dataset before build inverted index.
Also do not forget to add stopwords in stopwords.txt file.

The file tree must be like this:

├── dictionary.pkl (not necessary) ├── main.py ├── README.md ├── reuters21578 │   ├── lewis.dtd │   ├── README.txt │   ├── reut2-000.sgm │   ├── reut2-001.sgm │   ├── ... │   └── reut2-021.sgm ├── src │   ├── base.py │   ├── inverted_intex.py │   ├── query_processor.py │   └── sgm_preprocessor.py └── stopwords.txt

Programs run with python main.py command. Program gets input query and print result until q is given.

4 different query types are implemented:

1. Conjunction: w1 AND w2 AND w3...AND wn
   example: oil AND agriculture AND vegetable
   result: [3950, 5655, 7625, 8003, 9550, 9756, 10720, 14509, 15341, 18403, 20232]
2. Disjunction: w1 OR w2 OR w3...OR wn
   example: hate OR love OR cry
   result: 1895, 3148, 6338, 7366, 8827, 10890, 17099, 17903, 19559]
3. Conjunction and Negation: w1 AND w2...AND wn NOT wn+1 NOT wn+2 ...NOT wn+m
   example: oil AND agriculture AND vegetable NOT price
   result: [3950, 5655, 7625, 8003, 9550, 9756, 10720, 14509, 15341, 20232]
4. Disjunction and Negation: w1 OR w2...OR wn NOT wn+1 NOT wn+2 ...NOT wn+m
   example: hate OR love OR cry NOT money NOT price
   result: [1895, 3148, 6338, 7366, 8827, 10890, 17099]