我遇到了 Python 編程問題

Question

首先大家好，我是 stackoverflow 的新手。 如果我有任何錯誤，請告訴我。

我有一個作業要在星期二交，這個作業必須在 Python 完成。但是，我的項目有問題，我會嘗試在這里解決它，因為我不明白問題是什么。 如果你能幫忙，我會很高興。

注意：這個項目是“一個從用戶那里獲取客戶類型和貸款金額並打印前 12 個月貸款金額列表的程序。”

我報錯頁面的整體代碼結構是這樣的：

consumertype = ['mortgage', 'individual', 'corporation']
interestrate = [15.3, 25.2, 20.4]

consumertype = input("Enter your consumer type: ")
loanamount = float(input("Enter your loan amount"))



if consumertype =='mortgage':
    print("interst rate of mortgage is", 15.3)
if consumertype =='individual':
   print("interest rate of individual is", 25.2)
if consumertype =='corporation':
    print("interest rate of corporation is", 20.4)


  

for i in range(12):
    totalinterest = loanamount * (interestrate/100)*(i+1)
    totalpayment = totalinterest + loanamount
    monthlypayment = totalpayment/12


TimeRange = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
for i in TimeRange:
    print ("You will pay", monthlypayment, "$ on", TimeRange, "th.month")

問題：在第 20 行發現錯誤。但是，在我研究的資源中，我意識到不可能在列表中“列出”。 但是我完全不知道如何解決這個錯誤，因為我根本不明白 python。 我只想完成布置的作業，今年畢業。

它在第 20 行的終端中顯示錯誤。這正是第 20 行的代碼：

    totalinterest = loanamount * (interestrate/100)*(i+1)

我正在為您分享用可視化代碼截取的屏幕截圖，請查看此屏幕截圖並瀏覽終端。

你能幫我嗎？ 從現在開始謝謝你！

Answer 1

您可以更改這對列表

consumertype = ['mortgage', 'individual', 'corporation']
interestrate = [15.3, 25.2, 20.4]

聽寫

interest_rates = {
    'mortgage': 15.3,
    'individual': 25.2,
    'corporation': 20.4
}

然后獲取當前利率而不是

if consumertype =='mortgage':
    print("interst rate of mortgage is", 15.3)
if consumertype =='individual':
   print("interest rate of individual is", 25.2)
if consumertype =='corporation':
    print("interest rate of corporation is", 20.4)

你可以

try:
    interestrate = interest_rates[consumertype]
except KeyError:
    raise KeyError(f'Invalid consumer type entered: {consumertype}')

然后，對於您剩余的代碼， interstrate將是一個float而不是列表來進行計算。

Answer 2

Interestrate 是一個列表，所以有錯誤的行將不起作用。

您需要一種將消費者類型鏈接到利率的方法，這可以通過字典來完成：

interest_rates ={'mortgage': 15.3, 'individual': 25.2, 'corporation': 20.4}

然后，您可以從消費者類型的輸入中獲取利率：

interestrate = interest_rates.get(consumertype)

更正后的代碼：

interest_rates = {'mortgage': 15.3, 'individual': 25.2, 'corporation': 20.4}

consumertype = input("Enter your consumer type: ")
loanamount = float(input("Enter your loan amount"))

interestrate = interest_rates.get(consumertype)

if consumertype == 'mortgage':
    print("interst rate of mortgage is", 15.3)
if consumertype == 'individual':
    print("interest rate of individual is", 25.2)
if consumertype == 'corporation':
    print("interest rate of corporation is", 20.4)

for i in range(12):
    totalinterest = loanamount * (interestrate / 100) * (i + 1)
    totalpayment = totalinterest + loanamount
    monthlypayment = totalpayment / 12
    print("You will pay", monthlypayment, "$ on", (i+1), "th.month")

Answer 3

傑克。 您面臨的問題是因為interestrate是一個列表，因此不能除以int類型的100 。 我注意到有幾種方法可以改進代碼。 以下是我的建議：

1. 使用字典將 map 的interestrate列表轉為consumertype列表。

變化看起來像這樣：

consumertype = ['mortgage', 'individual', 'corporation']
interestrate = [15.3, 25.2, 20.4]

到

interest_rates = {
    'mortgage': 15.3,
    'individual': 25.2,
    'corporation': 20.4
}

2.不要在代碼中使用這么多if語句。 [除非必要]

從用戶處獲取consumertype和loanamount后，使用字典方法獲取該特定consumertype的interestrate值。

我建議的更改如下所示：

if consumertype =='mortgage':
    print("interst rate of mortgage is", 15.3)
if consumertype =='individual':
   print("interest rate of individual is", 25.2)
if consumertype =='corporation':
    print("interest rate of corporation is", 20.4)

到

if (interestrate:=interest_rates.get(consumertype, None)):
    print("Interest rate of mortgage is", interestrate)
else:
    print("Please verify if the right consume type is entered.")

3. 盡可能避免代碼重復。

正如您在代碼中看到的那樣，有兩個循環基本上運行相同的次數。 如果仔細觀察，您會發現可以將這兩個循環結合起來。

所以改變是

for i in range(12):
    totalinterest = loanamount * (interestrate/100)*(i+1)
    totalpayment = totalinterest + loanamount
    monthlypayment = totalpayment/12


TimeRange = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
for i in TimeRange:
    print ("You will pay", monthlypayment, "$ on", TimeRange, "th.month")

到

for i in range(12):
    totalinterest = loanamount * (interestrate/100)*(i+1)
    totalpayment = totalinterest + loanamount
    monthlypayment = totalpayment/12
    print ("You will pay", monthlypayment, "$ on", i+1, "th.month")

最終代碼

interest_rates = {
    'mortgage': 15.3,
    'individual': 25.2,
    'corporation': 20.4
}

consumertype = input("Enter your consumer type: ")
loanamount = float(input("Enter your loan amount: "))

if (interestrate:=interest_rates.get(consumertype, None)):
    print("Interest rate of mortgage is", interestrate)
else:
    print("Please verify if the right consume type is entered.")


for i in range(12):
    totalinterest = loanamount * (interestrate/100)*(i+1)
    totalpayment = totalinterest + loanamount
    monthlypayment = totalpayment/12
    print ("You will pay", monthlypayment, "$ on", i+1, "th.month")

注意：代碼需要Python3.8或更高版本。

參考：

1. ":=" 運算符： https://realpython.com/python-walrus-operator/
2. 詞典： https://realpython.com/python-dicts/

Answer 4

與該問題相關的主要問題是interestrate是一個列表而不是數字類型，因此算術運算失敗。 這個問題可以通過使用字典來解決：

interestrate = {'mortgage':15.3, 'individual':25.2, 'corporation':20.4}

並用interestrate interestrate[consumrtype]替換 interrate
雖然不是當前問題，但該代碼還有其他幾個已在此代碼中解決的問題：

# Using Dicts Instead of a list to prevent extra time consumption in searching
interestrate = {'mortgage':15.3, 'individual':25.2, 'corporation':20.4}

consumertype = input("Enter your consumer type: ")
loanamount = float(input("Enter your loan amount"))



if consumertype =='mortgage':
    print("interst rate of mortgage is", 15.3)
if consumertype =='individual':
   print("interest rate of individual is", 25.2)
if consumertype =='corporation':
    print("interest rate of corporation is", 20.4)


  

for i in range(12):
    # Here interestrate[consumertype] refers to the interest rate of the consumer
    # type entered by the user
    totalinterest = loanamount * (interestrate[consumertype]/100)*(i+1)
    totalpayment = totalinterest + loanamount
    monthlypayment = totalpayment/12
    # There is no need of using a another function as it will unnecessarily increase 
    # the complexity, so Here we display the interest at the same time as 
    # calculating it
    print ("You will pay", monthlypayment, "$ on", i+1, "th.month")

Answer 5

由於您的輸入之一是“消費者類型”，我猜測您正在嘗試顯示消費者類型和一年中每個月的每月支付金額，給定與該消費者類型相關聯的利率。

我建議您創建一個字典，將消費者類型與利率聯系起來，如下所示：

Interest_Dict={"Mortgage": 15.3, "Individual": 25.2, "Corporation": 20.4}

然后在計算每月還款額的這部分代碼中，您必須用 Interest_Dict[consumertype] 替換 interestrate

for i in range(12):
    totalinterest = loanamount * (Interest_Dict[consumertype]/100)*(i+1)
    totalpayment = totalinterest + loanamount
    monthlypayment = totalpayment/12

您用於獲取每月付款金額的 for 循環不正確。 您需要更改 for 循環，但根據您的公式，您根本不需要循環。

可以使用以下任何公式直接找到每月支付金額： https://www.thebalance.com/loan-payment-calculations-315564#:~:text=To%20calculate%20the%20monthly%20payment,per% 20年%20次%2030%20年）