frequentitemset.py

import math
from itertools import combinations




def read_data_in_dict(filename):
    f = open(filename)
    lines = f.readlines()
    transactions = []
    items = lines[0].split(',')
    for line in lines[1:]:
        transactions.append(list(map(int,line.split(','))))
    data ={
        'items':items,
        'transactions':transactions
    }
    return data



data=read_data_in_dict('itemsets.csv')
print(data);



def get_freq(s,items,transactions):
    freq=0
    for t in transactions:
        temp=1
        for item in s:
            temp*=t[items.index(item)]
        if temp==1:
            freq+=1  
    return freq



def frequent_itemsets(data,level,min_support):
    items = data['items']
    transactions = data['transactions']
    min_freq = math.ceil(min_support*len(transactions))
    sets = list(combinations(items,level))
    frequent_sets = []
    for s in sets:
        freq=get_freq(s,items,transactions)
        if freq>=min_freq:
            frequent_sets.append(s)
    return frequent_sets
        


print("frequent item sets")
print(frequent_itemsets(data,2,0.5))