在for循環中計算運行總數 - Python

Question

編輯：下面是基於我收到的反饋/答案的工作代碼。

這個問題源於我以前使用MIT開放課件學習Python/CS時出現的問題。 - See my previous question here -

我使用下面的代碼來製作月付款和其他東西的列表。然而，在循環結束時，我需要爲每個月支付的總金額計算總計。

原始代碼

balance = float(raw_input("Outstanding Balance: ")) 
interestRate = float(raw_input("Interest Rate: ")) 
minPayRate = float(raw_input("Minimum Monthly Payment Rate: ")) 

for month in xrange(1, 12+1): 
    interestPaid = round(interestRate/12.0 * balance, 2) 
    minPayment = round(minPayRate * balance, 2) 
    principalPaid = round(minPayment - interestPaid, 2) 
    remainingBalance = round(balance - principalPaid, 2) 


    print 'Month: %d' % (month,) 
    print 'Minimum monthly payment: %.2f' % (minPayment,) 
    print 'Principle paid: %.2f' % (principalPaid,) 
    print 'Remaining balance: %.2f' % (remainingBalance,) 

    balance = remainingBalance 

    if month in xrange(12, 12+1): 
     print 'RESULTS' 
     print 'Total amount paid: ' 
     print 'Remaining balance: %.2f' % (remainingBalance,) 

的問題是，我一直無法弄清楚如何保持一個運行總計支付的數額。我試着加入totalPaid = round(interestPaid + principalPaid, 2)，但是總共只有一個月，我似乎無法讓它保持每個月的價值，然後將它們全部加到最後打印出來。

我也知道，所產生的量應該是這樣，當每個值是知道的，通過列表的1131.12

我發現有很多的例子，但我似乎無法正確推斷出。

固定碼

balance = float(raw_input("Outstanding Balance: ")) 
interestRate = float(raw_input("Interest Rate: ")) 
minPayRate = float(raw_input("Minimum Monthly Payment Rate: ")) 
totalPaid = 0 

for month in xrange(1, 12+1): 
    interestPaid = round(interestRate/12.0 * balance, 2) 
    minPayment = round(minPayRate * balance, 2) 
    principalPaid = round(minPayment - interestPaid, 2) 
    remainingBalance = round(balance - principalPaid, 2) 
    totalPaid += round(minPayment, 2) 

    print 'Month: %d' % (month,) 
    print 'Minimum monthly payment: %.2f' % (minPayment,) 
    print 'Principle paid: %.2f' % (principalPaid,) 
    print 'Remaining balance: %.2f' % (remainingBalance,) 

    balance = remainingBalance 

    if month in xrange(12, 12+1): 
     print 'RESULTS' 
     print 'Total amount paid: %.2f' % (totalPaid,) 
     print 'Remaining balance: %.2f' % (remainingBalance,) 

Answer 1

你的循環之前，初始化變量累積值：

total_paid = 0 

，然後在你的循環體，適量添加到它。您可以使用+=運算符添加到現有變量，例如

total_paid += 1 

是total_paid = total_paid + 1的簡寫。您不希望每次迭代都給total_paid一個新值，而是希望增加其現有值。

我不確定您的問題的具體情況，但這是循環累計值的一般形式。

Answer 2

你確實有totalPaid初始化爲0，然後

totalPaid = round(interestPaid + principalPaid, 2) + totalPaid 

在循環中。你的問題是你沒有積累總數，你只是在每次迭代中設置一個新的。

Answer 3

聽起來像你接近。問題是你每次都覆蓋總數。嘗試這樣的：

totalPaid = totalPaid + round(interestPaid + principalPaid, 2) 

Answer 4

您總是支付最低費用？只需使用minPayment，而不是再次計算出數學。保持運行總數，然後在循環後打印出。

balance = float(raw_input("Outstanding Balance: ")) 
interestRate = float(raw_input("Interest Rate: ")) 
minPayRate = float(raw_input("Minimum Monthly Payment Rate: ")) 
paid = 0 

for month in xrange(1, 12+1): 
    interestPaid = round(interestRate/12.0 * balance, 2) 
    minPayment = round(minPayRate * balance, 2) 
    principalPaid = round(minPayment - interestPaid, 2) 
    remainingBalance = round(balance - principalPaid, 2) 
    paid += minPayment 

    print # Make the output easier to read. 
    print 'Month: %d' % (month,) 
    print 'Minimum monthly payment: %.2f' % (minPayment,) 
    print 'Principle paid: %.2f' % (principalPaid,) 
    print 'Remaining balance: %.2f' % (remainingBalance,) 

    balance = remainingBalance 

print 
print 'RESULTS' 
print 'Total amount paid:', paid 
print 'Remaining balance: %.2f' % (remainingBalance,) 

另請注意，該範圍只有一個值，所以您只需檢查月份== 12，但在這裏根本沒有必要。