Python:如何使用用户输入来关闭或继续 while 循环

Question

我是 python 的新手，仍在努力弄清楚基础知识。我在网上寻找答案，但似乎没有任何解决方案适合我。我不知道我是否遗漏了一些小东西，或者我的整体结构是错误的。我的代码的计算部分按预期工作。

我的问题是，我不知道如何要求用户输入是或否导致:

(回答 YES 重新开始循环，以便用户可以尝试另一个计算)

(答案不关闭循环/结束程序)

请告诉我您的建议!

    play = True

while play:

    hours = float(input("Please enter the number of hours worked this week: "))
    rate = float(input("Please enter your hourly rate of pay: "))

    #if less than 40 hrs
    if hours <= 40:
        pay = hours * rate
        print "Your pay for this week is",pay

    #overtime 54hrs or less   
    elif hours > 40 < 54:
        timeandhalf = rate * 1.5
        pay = (40 * hours * rate) + ((hours - 40) * timeandhalf)
        print "Your pay for this week is",pay 

    #doubletime more than 54hrs        
    elif hours > 54:
        timeandhalf = rate * 1.5
        doubletime = rate * 2
        pay = (40 * hours * rate) + ((hours - 40) * timeandhalf) + ((hours - 54) * doubletime)
        print "Your pay for this week is",pay    


    answer = (input("Would you like to try again?: "))
    if str(answer) == 'yes':
        play = True
    else:
        play = False

Answer 1

您正在使用 Python 2.x。 input() 尝试将输入作为有效的 Python 表达式运行。当你输入一个字符串时，它会尝试在命名空间中寻找它，如果找不到它就会抛出一个错误:

NameError: name 'yes' is not defined

您不应该使用 input 来接收未经过滤的用户输入，这可能很危险。相反，使用 raw_input()返回一个字符串:

play = True

while play:

    hours = float(raw_input("Please enter the number of hours worked this week: "))
    rate = float(raw_input("Please enter your hourly rate of pay: "))

    #if less than 40 hrs
    if hours <= 40:
        pay = hours * rate
        print "Your pay for this week is",pay

    #overtime 54hrs or less   
    elif hours > 40 < 54:
        timeandhalf = rate * 1.5
        pay = (40 * hours * rate) + ((hours - 40) * timeandhalf)
        print "Your pay for this week is",pay 

    #doubletime more than 54hrs        
    elif hours > 54:
        timeandhalf = rate * 1.5
        doubletime = rate * 2
        pay = (40 * hours * rate) + ((hours - 40) * timeandhalf) + ((hours - 54) * doubletime)
        print "Your pay for this week is",pay    

    answer = raw_input("Would you like to try again?: ").lower()
    while True:
        if answer == 'yes':
            play = True
            break
        elif answer == 'no':
            play = False
            break
        else:
            answer = raw_input('Incorrect option. Type "YES" to try again or "NO" to leave": ').lower()