如何让乘法键都存在于字典中？ (python)

Question

我有问题。

我想添加相同的记录，但旧记录将被新记录取代！我希望它们都存在，这样我就可以看到我做了什么。

我该如何解决这个问题？请帮助我！

谢谢！

我的代码：

initial_money = int(input('How much money do you have? '))
mr={}
add_mr={}
def records():
    return

def add(records):
    records = input('Add an expense or income record with description and amount:\n').split()
    
    global mr
    global rec
    rec = records[0]
    global amt
    amt = records[1]
    
    for r, a in mr.items():
        i = 0
        while (r, i) in add_mr:
            i += 1
        add_mr[(r, i)] = a
    
    global initial_money
    mr[rec] = int(amt)
    initial_money += mr[rec]
    
def view(initial_money, records):
    print("Here's your expense and income records:") 
    print("Description          Amount")
    print("-------------------  ------")
    for r,a in mr.items():
        print('{name:<20s} {number:<6s}'.format(name = r,number = str(a)))
    print('Now you have {} dollars.'.format(initial_money))   
    
while True:
    command = input('\nWhat do you want to do (add / view / delete / exit)? ')
    if command == 'add':
        records = add(records)
    elif command == 'view':
        view(initial_money, records)

输出：

How much money do you have? 1000

What do you want to do (add / view / delete / exit)? add
Add an expense or income record with description and amount:
ewq 87

What do you want to do (add / view / delete / exit)? add
Add an expense or income record with description and amount:
ewq 87

What do you want to do (add / view / delete / exit)? view
Here's your expense and income records:
Description          Amount
-------------------  ------
tree                  87    
Now you have 1174 dollars.

我想要的输出：

-------------------  ------
tree                  87
tree                  87

Answer 1

与其使用 Mr = {"ewq": 87} 这样的字典，不如使用包含所有这些的列表 Mr = [("ewq", 87), ("ewq", 87)]

这样一来，即使您有副本，也不会被覆盖。因为字典每个键只能有一个

编辑：您可以通过将 mr = {} 的第一部分替换为 mr = [] 来做到这一点，然后每当您调用 addmr 时，您可以只使用 mr.append(value)将值添加到列表

Answer 2

你实际上可以用字典来做到这一点。每个键使用一个列表，而不是每个键一个项目。

if rec not in mr:
    mr[rec] = []
mr[rec].append(amt)

这样 mr = {"ewq": [87, 87]}

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