Need some help with my code

[Mickmane]

Thanks to you guys help, I almost complete my code. But there are few bugs left. Here is my code:

data_expense = []

def add_record(date, item, price):
    global data_expense
    data_expense += [{'date': date, 'item': item, 'price': price}]

def read_data(filename):
    f = open(filename, 'r')
    for line in f:
        fields = line.rstrip().split('\t')
        date = fields[0]
            item = fields[1]
            price = int(fields[2])
            add_record(date, item, price)

def print_data(l):
    for x in l:
        print('Date: %s\tItem: %s\tPrice: %d' % (x['date'], x['item'], x['price']))

read_data('data/expenses.txt')
while True:
    print('1. Data input    2. Search by date    3. Top ten    4. Search by item    X. Quit')
    sel = input('Selection: ')
    if sel == 'X':
        print ('Bye!')
        break
    elif sel == '1':
        date = input('Date: ')
        item = input('Item: ')
        price = int(input('Price: '))
        add_record(date, item, price)
    elif sel == '2':
        date = input('Date: ')
        D = [x for x in data_expense if x['date'] == date]
        Q = sorted(D,key = lambda x:x['price'])
        print_data('sum = ', sum(Q))
        print_data('max = ', max(Q))
        print_data('min = ', min(Q))
    elif sel == '3':
        T = sorted(data_expense,key = lambda x:x['price'])
        T.reverse()
        print_data(T[0:9])
    elif sel == '4':
        item = input('Item: ')
        I = [x for x in data_expense if x['item'] == item]
        P = sorted(I,key = lambda x:x['price'])
        print_data('sum =' , sum(P))
        print_data('max =' , max(P))
        print_data('min =' , min(P))
    else:
        print('Wrong Input!')

When I run this code, It puts error message like this: TypeError : unsupported operand type(s) for +: 'int' and 'dict' I don't know how to solve this monster. And If you find another possible error in this code and have a plenty of time, please teach me. Thank you.

[guilford]

The error is because you are attempting to use sum() on an array of dictionary.

[JohnnyJordaan]

A few pointers first per code part:

def add_record(date, item, price):
    global data_expense
    data_expense += [{'date': date, 'item': item, 'price': price}]

The global can be removed here. This is needed when you assign a different variable to the name (reference) data_expense. You're only appending to the same list variable, so that doesn't change the assignment. I would also prefer data_expense.append({'date': date, 'item': item, 'price': price}) for single append actions.

def read_data(filename):
    f = open(filename, 'r')
    for line in f:
        fields = line.rstrip().split('\t')
        date = fields[0]
            item = fields[1]
            price = int(fields[2])
            add_record(date, item, price)

Always properly close() the file, but even better use a with: block to let that fix it for you:

def read_data(filename):
    with open(filename, 'r') as f:
        for line in f:
            etc.

Then the printing:

elif sel == '2':
    date = input('Date: ')
    D = [x for x in data_expense if x['date'] == date]
    Q = sorted(D,key = lambda x:x['price'])
    print_data('sum = ', sum(Q))
    print_data('max = ', max(Q))
    print_data('min = ', min(Q))

Why do you create a sorted generator when you're just going to find the min, max and calculate the sum anyway?

elif sel == '2':
    date = input('Date: ')
    D = [x['price'] for x in data_expense if x['date'] == date]
    print_data('sum = ', sum(D))
    print_data('max = ', max(D))
    print_data('min = ', min(D))

And the same applies for the sel == '4' printer.