环路不工作时

Question

不久前，我的任务是设计一个货币兑换器，作为我学校项目的一部分。我记得包括了一个“while循环”，它非常有效。然而，当我再次回顾该程序并对其进行测试时，while循环不再起作用。在

我希望有人能解释while循环不起作用的原因。也许它从来没有起作用，我只是记错了，或者是代码中的某些变化导致它不能工作？在

while True:  #first while loop - repeats entire program unless broken 
while True: #second while loop - repeats input section of code unless broken
    currentcurrency = input ("Select a starting currency: ") #allows user to input their starting currency, saved as a string in variable 'currentcurrency'
    print ('You selected %s' % currentcurrency) #prints inputted string

    value = float(input ("Input your current value: ")) #allows user to input their value of money, saved as a float in variable 'value'

    newcurrency =  input ("Select a new currency: ")  #allows the user to input their new currency, saved as a string in variable 'newcurrency' 
    if currentcurrency == 'Pound' and newcurrency == 'Pound': #this part of the code determines the convertor value based upon the two inputted currencies
        convertor = 1
    if currentcurrency == 'Pound' and newcurrency == 'Euro':
        convertor = 1.34
    if currentcurrency == 'Pound' and newcurrency == 'Dollar':
        convertor = 1.46
    if currentcurrency == 'Pound' and newcurrency == 'Yen':

        convertor = 171.61
    if currentcurrency == 'Euro' and newcurrency == 'Pound':
        convertor = 0.75

    if currentcurrency == 'Euro' and newcurrency == 'Euro':
        convertor = 1
    if currentcurrency == 'Euro' and newcurrency == 'Dollar':
        convertor = 1.09
    if currentcurrency == 'Euro' and newcurrency == 'Yen':
        convertor = 127.47
    if currentcurrency == 'Dollar' and newcurrency == 'Pound':
        convertor = 0.69
    if currentcurrency == 'Dollar' and newcurrency == 'Euro':
        convertor = 0.88
    if currentcurrency == 'Dollar' and newcurrency == 'Dollar':
        convertor = 1
    if currentcurrency == 'Dollar' and newcurrency == 'Yen':
        convertor = 121.12
    if currentcurrency == 'Yen' and newcurrency == 'Pound':
        convertor = 0.0062
    if currentcurrency == 'Yen' and newcurrency == 'Euro':
        convertor = 0.0076
    if currentcurrency == 'Yen' and newcurrency == 'Dollar':
        convertor = 0.0083
    if currentcurrency == 'Yen' and newcurrency == 'Yen':
        convertor = 1

    print ("Do you want to convert", (value), (currentcurrency), "to", (newcurrency), "?")
    answer = input ("Yes/No: ")  #allows the user to input a response, saved in variable 'answer'
    if answer == 'Yes' or 'y' or 'yes': #if the user inputted string is 'Yes' or equivelant,
        break                           #the while loop will break, and the program will continue

result = (convertor) * (value)          #calculates the result by multiplying the user inputted value and the converter
result *= 100                           #this part of the code calculates the result to two decimal places
result += 0.5                           #it multiplies the result by 100 and adds 0.5
result = int(result)                    #then changes the result to an integer
result /= float(100)                    #divides the result by a 100 and changes it to a float
print (result, newcurrency)             #prints the result, followed by the new currency

answer2 = input("Do you want to convert again? (Yes/No): ") #allows the user to input an answer
if answer2 == 'No' or 'n' or 'no': #if the inputted answer is 'No' or equivalent,
    break                          #the while loop breaks and the code continues - otherwise, it repeasts the program
exit()                                 #ends the program 

谢谢，请简单解释一下，因为我对这个项目不是很有经验！在

编辑：格式错误。实际代码如下所示： Currency Converter

Answer 1

这里有两个嵌套循环，因此第二个需要缩进两个：

while True:  
    while True: #requires indentation
        currentcurrency = input ("Select a starting currency: ")
        [...]