如何在python中使用两个条件循环？

如何解决如何在python中使用两个条件循环？

我需要编写一个代码，显示0到20年或当今天的价值达到投资初始投资金额的.5 *时的投资回报。我被后者困住了。当我使用IF语句时，我什么也得不到。这是我的代码。

def getExpInvestAmt(investAmt,i,n):
    expInvestAmt = int(investAmt * pow(1 + i / 100,n))
    return expInvestAmt

def getPresentValue(exp_invest_amt,d,n):
    adjAmt = int(exp_invest_amt / pow(1 + d / 100,n))
    return adjAmt


def main():
    investAmt = float(input("Enter investment amount:"))
    i = float(input("Enter the expected investment growth rate:"))
    d = float(input("Enter the discount rate:"))
    n = 0
    adjA = 0
    print("Year \t Value at year($) \t Today's worth($)")
    for x in range(0,21):  
        if adjA < 0.5 * investAmt
            break 
        expected_value = getExpInvestAmt(investAmt,n)
        present_value = getPresentValue(expected_value,n)
        n += 1
        adjA += 1
        print("{} \t {:,} \t {:,}".format(x,expected_value,present_value))


main()

这就是我应该得到的，

Enter investment amount: 10000
Enter the expected investment growth rate: 5
Enter the discount rate: 6.25
Year Value at Year($) Today's worth($)
 1       10,500           9,346
 2       11,025           8,734
 3       11,576           8,163
 4       12,155           7,629
 5       12,763           7,130
 6       13,401           6,663
 7       14,071           6,227
 8       14,775           5,820
 9       15,513           5,439
 10      16,289           5,083
 11      17,103           4,751  # today's value have reached <= 50% of the initial amount program stops.

解决方法

我认为您可以简化代码；您不需要adjA或x。在使用adjA的地方，您应该只使用present_value，并且可以在范围内迭代n而不是x：

def main():
    investAmt = float(input("Enter investment amount:"))
    i = float(input("Enter the expected investment growth rate:"))
    d = float(input("Enter the discount rate:"))
    print("Year \t Value at year($) \t Today's worth($)")
    for n in range(1,21):  
        expected_value = getExpInvestAmt(investAmt,i,n)
        present_value = getPresentValue(expected_value,d,n)
        print("{} \t {:,} \t {:,}".format(n,expected_value,present_value))
        if present_value < 0.5 * investAmt:
            break 

要获得investAmt为10000和i为5的预期结果，您需要d的值为12.347528。