Question

我是Python的新手，想知道为什么会发生这种情况。这是代码：

import turtle


What_Calculate = turtle.numinput("Area of Different Shapes Calculator", "Type 1 to calculate the area of a square, Type 2 to calulate the area of a rectangle, Type 3 to calculate the area if a triangle, Type 4 to calulate the area of a circle, or click [q] to quit:")

while What_Calculate !="q":

    if What_Calculate == 1:
        Length_Square = eval(input("What is the length of the square?:"))
        Area_Squ = Length_Square * Length_Square
        print("The area of the square is ", Area_Squ, ".")
        What_Calculate = input("Click another number or click [q] to exit:")

    elif What_Calculate == 2:
        Length_1 = eval(input("What is the first length?:"))
        Length_2 = eval(input("What is the second length?:"))
        Area_Rec = Length_1 * Length_2
        print("The area of the rectangle is ", Area_Rec, ".")
        What_Calculate = input("Click another number or click [q] to exit:")

    elif What_Calculate == 3:
        Length = eval(input("What is the length?:"))
        Height = eval(input("What is the height?:"))
        Area = Length * Height / 2
        print("The area of the triangle is", Area)
        What_Calculate = input("Click another number or click [q] to exit:")

    elif What_Calculate == 4:
        Diameter = eval(input("What's the diameter of the circle?:"))
        Radius = Diameter / 2
        Pie = 3.14
        Area = Pie * Radius * Radius
        print("The area of the circle is ", Area, ".")
        What_Calculate = input("Click another number or click [q] to exit:")

这是问题所在：用户输入了要使用的计算器后，代码便会起作用，直到给出答案为止。在What_Calculate = input("Click another number or click [q] to exit:")，键入q可以正常退出，但是1-4根本不起作用。如果我没看错，在这种情况下while循环不应该循环，直到What_Calculate为空？

Answer 1

问题是What_Calculate = input("Click another number or click [q] to exit:")返回一个字符串，该字符串在if / elif / elif / elif中总是失败。因为它是字符串而不是数字，所以"1" != 1。我可以看到的最简单的方法是添加

try:
    What_Calculate = int(What_Calculate)
except ValueError:
    #Some code to handle what happens if What_Calculate cannot be turned into an int.

到while循环的开始。将其包含在try / except循环中可让您检测用户是否输入了不是整数且不是字母'q'的内容。

Answer 2

input()返回一个字符串...您正在检查一个整数

Answer 3

input（）函数返回一个字符串，并且由于循环中的所有比较都是数字，因此它将在第一次通过后永远循环。您不应该同时将What_Calculate用作int和字符串-我的建议（尝试更改尽可能少的代码）是将比较从if What_Calculate == 1:更改为if What_Calculate == "1":依此类推，然后更改您的turtle.numinput调用以要求输入字符串而不是数字。

为什么while循环在第一次运行后不循环？ While循环无法读取变量的新值

3 个答案: