Question

我是Python编程的新手，并且在这个简单的程序中遇到了麻烦，该程序计算了2维的平铺价格：

目标：使用用户输入的成本计算覆盖宽度和高度平面图所需的平铺总成本。

print ("NOTE: The unit of cost is in dollars and dimension unit is in feet")

def cost_o_tile(cost, width, height):
    while True:
        cost = int(input("Cost of each tile:"))
        width = int(input("What is the width of the floor?"))
        height = int(input("What is the height of the floor?"))
        try:
            if cost < 0 or width < 0 or height <0:
                print ("\n Please enter non-negative integers")
                break
            else:
                 return ("In order to cover your {} X {} floor, you will need to pay {} dollars".format(width,height,cost*width*height))
        except ValueError: 
            print ("No valid integer! Please try again ...")


cost_o_tile(cost, width, height)

我知道我可以在函数之外声明变量，代码也可以。但是，我想在循环中使用这些变量，以便except ValueError验证它们。

Answer 1

好吧，你的函数cost_o_lite不应该带任何参数：

def cost_o_tile():
    ...

print(cost_o_tile())

不要忘记打印结果。

您也可以分开关注：

首先写一个算法来计算总费用：

def cost_o_tile(cost, width, height):
    if cost < 0 or width < 0 or height < 0:
        raise ValueError
    return cost * width * height

然后编写用户界面代码：

print ("NOTE: The unit of cost is in dollars and dimension unit is in feet")

while True:
    try:
        cost = int(input("Cost of each tile:"))
        width = int(input("What is the width of the floor?"))
        height = int(input("What is the height of the floor?"))
        total = cost_o_tile(cost, width, height)
        print("In order to cover your {} X {} floor, you will need to pay {} dollars"
              .format(width, height, total))
        break
    except ValueError:
        print ("No valid integer! Please try again ...")

Answer 2

使您的函数尽可能纯粹是编写良好，可维护代码的关键，这当然不包括潜在的无限循环和用户输入。

全局范围内没有变量cost，width或height。这是导致错误的原因。

输入代码必须移到
删除循环
一旦您的代码正常运行，您可以担心错误处理。

首次通过

def cost_o_tile(cost, width, height):
    return ("In order to cover your {} X {} floor, you will need to pay {} dollars"\
                          .format(width, height, cost * width * height))

cost, width, height = map(int, input("Enter 3 space separated integers: ").split())
print(cost_o_tile(cost, width, height))

第二次通过

一旦基本程序正常工作，您可以查看错误处理：

def cost_o_tile(cost, width, height):
    try:
        if cost < 0 or width < 0 or height < 0:
            return "Parameters cannot be lesser than 0"
    except ValueError:
        return "Please provide numbers only"

    return ("In order to cover your {} X {} floor, you will need to pay {} dollars"\
                          .format(width, height, cost * width * height))

cost, width, height = map(int, input("Enter 3 space separated integers: ").split())
print(cost_o_tile(cost, width, height))

最终通行证

现在，在处理错误后，您最终可以查看循环。

def cost_o_tile(cost, width, height):
    try:
        if cost < 0 or width < 0 or height < 0:
            return "Parameters cannot be lesser than 0"
    except ValueError:
        return "Please provide numbers only"

    return ("In order to cover your {} X {} floor, you will need to pay {} dollars"\
                          .format(width, height, cost * width * height))

if __name__ == '__main__':
    while True:
        cost, width, height = map(int, input("Enter 3 space separated integers: ").split())
        print(cost_o_tile(cost, width, height))

        if input("Continue? ").lower() not in {'y', 'ye', 'yes'}:
            break

Answer 3

cost_o_tile(cost, width, height)

当您在代码的第18行调用cost函数时，问题出在cost_o_tile参数上。如果你仔细观察，它还没有在函数范围之外定义，因此错误。

NameError：name＆＃39; cost＆＃39;未定义 - 调用函数

3 个答案: