Search_Engine/indexer.py

206 lines
6.3 KiB
Python

#We have to import the files
#Split the indexer into 4 parts
#Alphanumeric sequences into the dataset
#Stemming
#Text in bold, headings and other titles should be treated as more important
#Posting structure > tf-idf score. Name/id the token was found in . So hashmap.
#We need shelves to hold the data.
#Posting ---> Source of file, tf-idf score. #for now we will only use these two, as we get more complex posting will be change accordingly
#Data input
import json
import os
import shelve
from bs4 import BeautifulSoup
from time import perf_counter
#Data process
from nltk.tokenize import word_tokenize
from nltk.stem import PorterStemmer
from sklearn.feature_extraction.text import TfidfVectorizer
import pandas as pd
import numpy as np
import re
#Logging postings
from posting import Posting
class Indexer():
def __init__(self,restart,trimming):
#Config stuffs
self.path = "data/DEV/"
self.restart = restart
self.trimming = trimming
self.stemmer = PorterStemmer()
#Shelves for index
#https://www3.nd.edu/~busiforc/handouts/cryptography/letterfrequencies.html
#https://www.irishtimes.com/news/science/how-many-numbers-begin-with-a-1-more-than-30-per-cent-1.4162466
#According to this will be how we split things
#Save #1 = ABCD + (1) ~ 18.3% of words
#Save #2 = EFGHIJK + (2-3)~ 27.1% of words
#Save #3 = LMNOPQ + (4-7) ~ 25.4% of words
#Save #4 = RSTUVWXYZ + (8-9)~ 29.2% of words
#Save #5 = Special characters
if os.path.exists("save_1.shelve") and restart:
os.remove("save_1.shelve")
if os.path.exists("save_2.shelve") and restart:
os.remove("save_2.shelve")
if os.path.exists("save_3.shelve") and restart:
os.remove("save_3.shelve")
if os.path.exists("save_4.shelve") and restart:
os.remove("save_4.shelve")
if os.path.exists("save_5.shelve") and restart:
os.remove("save_5.shelve")
self.save_1 = shelve.open("save_1.shelve")
self.save_2 = shelve.open("save_2.shelve")
self.save_3 = shelve.open("save_3.shelve")
self.save_4 = shelve.open("save_4.shelve")
self.save_5 = shelve.open("save_5.shelve")
def save_index(self,word,posting):
cur_save = self.get_save_file(word)
shelve_list = list()
try:
shelve_list = cur_save[word]
shelve_list.append(posting)
tic = perf_counter()
shelve_list.sort(key=lambda x: x.tf_idf, reverse = True)
toc = perf_counter()
if toc - tic > 1 :
print("Took " + str(toc - tic) + "seconds to sort shelve list !")
cur_save.sync()
except:
shelve_list.append(posting)
cur_save[word] = shelve_list
cur_save.sync()
def get_save_file(self,word):
#return the correct save depending on the starting letter of word
word_lower = word.lower()
if re.match(r"^[a-d0-1].*",word_lower):
return self.save_1
elif re.match(r"^[e-k2-3].*",word_lower):
return self.save_2
elif re.match(r"^[l-q4-7].*",word_lower):
return self.save_3
elif re.match(r"^[r-z8-9].*",word_lower):
return self.save_4
else:
print(word)
print("You have somehow went beyond the magic")
return self.save_5
# I have a test file (mytest.py) with pandas but couldn't figure out how to grab just a single cell.
# so I came up with this, if anyone knows how to get a single cell and can explain it to
# me I would love to know, as I think that method might be quicker, maybe, idk it like
# 4am
# https://stackoverflow.com/questions/34449127/sklearn-tfidf-transformer-how-to-get-tf-idf-values-of-given-words-in-documen
def get_tf_idf(self,words,word):
#tf_idf
#words = whole text
#word the word we finding the score for
#return the score
vect = TfidfVectorizer()
tfidf_matrix = vect.fit_transform(words)
feature_index = tfidf_matrix[0,:].nonzero()[1]
feature_names = vect.get_feature_names_out()
tfidf_scores = zip(feature_index, [tfidf_matrix[0, x] for x in feature_index])
for w, s in [(feature_names[i], s) for (i, s) in tfidf_scores]:
if w == word:
return s
else:
return -1 # don't really know what to do if the word doesn't exist, we can catch with negative or print an error?
def get_data(self):
for directory in os.listdir(self.path):
for file in os.listdir(self.path + "/" + directory + "/"):
#Actual files here
#JSON["url"] = url of crawled page, ignore fragments
#JSON["content"] = actual HTML
#JSON["encoding"] = ENCODING
ticker = perf_counter()
tic = perf_counter()
file_load = open(self.path + "/" + directory + "/"+file)
data = json.load(file_load)
soup = BeautifulSoup(data["content"],from_encoding=data["encoding"])
words = word_tokenize(soup.get_text())
toc = perf_counter()
if toc - tic > 1 :
print("Took " + str(toc - tic) + "seconds to tokenize text !")
tokenized_words = list()
stemmed_words = list()
tic = perf_counter()
for word in words:
if word != "" and re.fullmatch('[A-Za-z0-9]+',word):
#So all the tokenized words are here,
tokenized_words.append(word)
toc = perf_counter()
if toc - tic > 1 :
print("Took " + str(toc - tic) + "seconds to isalnum text !")
#YOUR CODE HERE
tic = perf_counter()
for word in tokenized_words:
stemmed_words.append(self.stemmer.stem(word))
#stemming,
#tf_idf
#get_tf_idf(stemmed_words,word)
#post = Posting()
toc = perf_counter()
if toc - tic > 1 :
print("Took " + str(toc - tic) + "seconds to stemmed text !")
for word in stemmed_words:
#posting = Posting(data["url"],self.get_tf_idf(list(' '.join(stemmed_words)),word))
tic = perf_counter()
posting = Posting(data["url"],self.tf_idf_raw(stemmed_words,word))
toc = perf_counter()
if toc - tic > 1 :
print("Took " + str(toc - tic) + "seconds to tf_idf text !")
tic = perf_counter()
self.save_index(word,posting)
toc = perf_counter()
if toc - tic > 1 :
print("Took " + str(toc - tic) + "seconds to save text !")
tocker = perf_counter()
print("Finished " + data['url'] + " in \t " + str(tocker-ticker))
def tf_idf_raw(self,words,word):
tf_times = words.count(word)
tf = tf_times/len(words)
return tf
def main():
indexer = Indexer(True,0)
indexer.get_data()
if __name__ == "__main__":
main()