为什么我的非活跃变量会涨价？

Question

一个简单的程序来帮助我计算一些新地板的成本，但我的最终产出不是我所期望的。 特别是，当underlay为“No”时，underlayrea的变量仍在提取值并在末尾打印。 如果不是很明显，这是我第一次尝试。永远不会

我原以为，虽然“edging”和“underlay”的变量保持为“No”，但while循环中不会存储任何值

underlay='No'
edging=input('Are you ordering Edging?').title()
underlay=input('Are you ordering underlay?').title()
roomsize=input('How many square meters is the room?')
roomflt=float(roomsize)
while edging =='Yes':
    #ask for user inputs
    edgeprice=input("How much is the edging per meter?")
    edgeperim=input('What is the perimeter of the room?')
    #convert to float for calculation
    one=float(edgeperim)
    two=float(edgeprice)
    #calculate
    edgearea=one*two
    #reset flag
    edging='No'
while underlay=='Yes':
    #ask for user input
    underlayprice=input('How much per square meter for the Underlay?')
    #convert to float for calculation
    three=float(underlayprice)
    four=float(roomflt)
    #calculate
    underlayarea=three*four
    #reset flag
    underlay='No'
#set the floor price
floorprice=input("How much is the floor per square meter?")
#convert to float for calculation
five=float(floorprice)
six=float(roomflt)
#calculate
area=five*six
#get the cost
addemup=(edgearea+underlayarea+area)
print("\n----------------------------------------------\nThe total is £{0:.2f} to purchase the flooring.".format(addemup))
print("This is made up of £{0:.2f} for the floor itself,".format(area))
print("This is made up of £{0:.2f} for the edging,".format(edgearea))
print("and £{0:.2f} for the underlay".format(underlayarea))

Answer 1

应该使用简单的if-语句，而不是使用while-循环和循环底部的“重置标志”。我还通过给变量命名来提高代码的可读性（从不给变量命名，比如one、two等等）。您还必须定义edgearea和underlayarea，因为如果用户在至少一个输入中输入"No"，则会引发NameError

edgearea = 0
underlayarea = 0

edging = input('Are you ordering Edging?').title()
underlay = input('Are you ordering underlay?').title()
roomsize = input('How many square meters is the room?')
roomsize = float(roomsize)

if edging == 'Yes':
    edgeprice = float(input("How much is the edging per meter?"))
    edgeperim = float(input('What is the perimeter of the room?'))
    edgearea = edgeperim * edgeprice

if underlay == 'Yes':
    underlayprice = float(input('How much per square meter for the Underlay?'))
    underlayarea = underlayprice * roomsize

floorprice = float(input("How much is the floor per square meter?"))
area = floorprice * roomsize

total_price = edgearea + underlayarea + area
print(f"\n                       \nThe total is {total} to purchase the flooring.")
print(f"This is made up of {area} for the floor itself,")

if edgearea:
    print(f"This is made up of {edgearea} for the edging,")

if underlayarea:
    print(f"and {underlayarea} for the underlay")

我还想建议大家看看干法原理，也就是“不要重复你自己”。这三种计算形式基本相同。这就是为什么更好的代码风格是为这些计算定义一个函数，该函数采用必要的参数。干溶液可能类似于以下内容：

def calculate(
    name: str,
    dimension: str,
    unit: str,
    mandatory: bool = True,
) -> float:
    mandatory = mandatory or input(f"Do you order {name}?") == "Yes"
    if mandatory:
        relative_price = float(input(f"How much is the {name} per {unit}?"))
        size = float(input(f"How much {dimension} is the room?"))

        return size * relative_price

    return 0


floor_price = calculate("floor", "area", "squaremeters")
edging_price = calculate("edging", "perimeter", "meters", False)
underlay_price = calculate("underlay", "area", "squaremeters", False)

total_price = floor_price + edging_price + underlay_price