Question

The Python Question is as follows:

You have been asked by a manager of a store to identify the items most commonly bought together (the manager would like to place these items in close proximity).

You are given a file, receipts.txt , that contains the receipts of the last 1000 transactions in the following format, where each line of the file is a single receipt:

eggs, bread, milk, lettuce

cheese, milk, apples

bread, milk

bread, cheese, milk

Write a function in python that will open the file, process it, and run the most common combinations(combinations that occur at least twice). For the example above, you should return a dictionary containing :

{ (bread, milk) :3, (cheese, milk) :2 }

NOTE: Code in python.

Answer 1

def createDictionary():
    itemDict = dict()
    with open('receipts.txt', 'r') as file:
        #Read complete content
        content = file.readlines()
  
        #Now process line by line
        for line in content:
            #items will store each item in a single line
            items = list()
            #Store items in a temporary list first
            temp = line.split(',')
            for item in temp:
                items.append(item.strip())
          
            #In a dictionary we can have tuple as a key.
            #Since (a,b) is same as (b,a).
            #To avoid issues due to order of the pair generated,
            #we will first create a pair
            #Then sort it using sorted() function for lists
            #Then convert it to tuple. Thus every pair of a & b will be (a,b) only.
      
            #Create item pairs and store in itemDict
            for i in range(len(items)-1):
                for j in range(i+1, len(items)):
                    pair = [items[i], items[j]]
                    pair = sorted(pair)
                    pair = tuple(pair)
              
                    #If pair found in itemDict, increment frequency else set it to 1
                    if pair in itemDict.keys():
                        itemDict[pair] = itemDict[pair] + 1
                    else:
                        itemDict[pair] = 1
                  
    #Generate Initial dictionary
    for key, value in itemDict.items():
        print(key, value)
  
    #Create dictionary with frequencies more than or equal to 2 only
    finalDict = dict()
    for key, value in itemDict.items():
        if value>=2:
            finalDict[key] = value

    print()
    #Print final dictionary
    for key, value in finalDict.items():
        print(key, ":", value)
  
    return(finalDict)

Initial outputs are the raw dictionary generated, includeing frequency of 1 also.

Then final dictionary has been generated and printed with frequency of 2 or more only.

Remove the print statements that you do not need.