parse.py

import json
import locale
import re
import sys
############################################### MAKE SURE TO RUN python create.py BEFORE RUNNING THIS SCRIPT.##############################
# SYNTAX: python parse.py -q "attribute1 = value1, attribute2 = value2, attribute3 < value3 ..." -a "attribute1, attribute2, attribute3 ..." -c
#-q is used to denote that succeeding string is conditions
#-a is used to denote that succeeding string is attributes projected in query
#-c is used to print the number of data entries in the view
#FOR EXAMPLE: python parse.py -q "tag = Childrens, price > 12.23, rating = Two" -a "title, price"
#rating are in words with first letter capital
#tags are case-sensitive
#tags ={Travel, Mystery, Historical Fiction, Sequential Art, Classics, Philosophy, Romance, Womens Fiction, Fiction, Childrens, Religion, Nonfiction, Music, Default, Science Fiction, Sports and Games, Add a comment, Fantasy, New Adult, Young Adult, Science, Poetry, Paranormal, Art, Psychology, Autobiography, Parenting, Adult Fiction, Humor, Horror, History, Food and Drink, Christian Fiction, Business, Biography, Thriller, Contemporary, Spirituality, Academic, Self Help, Historical, Christian, Suspense, Short Stories, Novels, Health, Politics, Cultural, Erotica, Crime}
#rating = {One, Two, Three, Four, Five}
#attributes : {tag, title, rating, price, image_urls, product_desc}
##############################################################################################################################################
def project(view, attribute_list, count):
    strings = []
    attribute_list_full = ['tag', 'title', 'rating', 'price', 'image_urls', 'product_desc']

    if len(attribute_list) == 0:
        attribute_list = attribute_list_full[:]

    for entry in view:
        s = {}
        for attribute in attribute_list:
            s[attribute] = entry[attribute]
        strings.append(s)
    if count:
        print(len(strings))
    with open('query_result', 'w') as f:
        json.dump(strings, f)


def is_number(parameter_i):
    if parameter_i.isdigit():
        parameter_i = int(parameter_i)
    elif parameter_i.replace('.', '', 1).isdigit():
        parameter_i = float(parameter_i)
    return parameter_i


def check(instance, condition_list):
    for condition in condition_list:
        parameter1 = condition['attr1']
        parameter2 = condition['attr2']
        decimal_point_char = locale.localeconv()['decimal_point']
        if parameter1 == 'price':
            v2 = float(re.sub(r'[^0-9' + decimal_point_char + r']+', '', parameter2))
            v1 = float(re.sub(r'[^0-9' + decimal_point_char + r']+', '', instance[parameter1]))
        else:
            v2 = parameter2
            v1 = instance[parameter1]
        operator = condition['o']
        if (operator == '=' and v1 != v2):
            return False
        if ((operator == '>') and v1 <= v2):
            return False
        if ((operator == '<') and v1 >= v2):
            return False
        if ((operator == '>=') and v1 < v2):
            return False
        if ((operator == '<=') and v1 > v2):
            return False
    return True


def sigma(db, condition_list):
    if (len(condition_list) == 0):
        return db
    view = []
    for entry in db:
        if check(entry, condition_list):
            view.append(entry)
    return view


def read_input():
    option_1 = ''
    line_1 = ''
    option_2 = ''
    line_2 = ''
    option_3 = ''
    count = False

    try:
        option_1 = sys.argv[1]
        line_1 = sys.argv[2]
        option_2 = sys.argv[3]
        line_2 = sys.argv[4]
        option_3 = sys.argv[5]
    except:
        pass

    condition_list = []
    attribute_list = []
    if option_1 == '-q':
        condition_list = [dict(zip(['attr1', 'o', 'attr2'], list(condition.split()))) for condition in
                          list(line_1.split(', '))]

    if option_2 == '-a':
        attribute_list = list(line_2.split(', '))

    if option_3 == '-c':
        count = True

    return {'q': condition_list, 'a': attribute_list, 'c': count}


def main():
    par = read_input()
    with open('data_base.json', 'r') as f:
        db = json.load(f)
    # print (db)
    view = sigma(db, par['q'])
    project(view, par['a'], par['c'])


if __name__ == '__main__':
    main()