Question

所以我有这个短程序，应该给出一个形状的区域。当我在调用它时给which_area(x)赋值时，它可以正常工作。但是当我将raw_input()作为参数时，（并且因为我将print choose_area放在底部），shell在输入后回复None。

我不太确定出了什么问题，但我认为它与return声明以及我如何表达它有关。

任何帮助表示赞赏:)请，谢谢。

从一开始的程序员。

def triangle_area():
    print "What is the base length?"
    base = raw_input()
    print "What is the height?"
    height = raw_input()
    area = 0.5*float(base)*float(height)
    print "The area of you triangle is:", area

def circle_area():
    print "What is the radius of the circle?"
    radius = raw_input()
    area = 3.14159*(float(radius)**2)
    print "The area of your circle is:", area

def square_area():
    print "What is the length of the side of the square?"
    print "(Remember that squares have equal sides, and if"
    print "you want to enter a seperate length and width"
    print "you have a rectangle.)"
    length = raw_input()
    area = float(length)**2
    print "The area of your square is", area

def which_area(x):
    if x == 1:
        return triangle_area()
    elif x == 2:
        return circle_area()
    elif x == 3:
        return square_area()
    else:
        return "You didn't pick 1, 2, or 3."

def choose_area():
    print "Calculate the area of which shape?"
    print "1. a triangle"
    print "2. a circle"
    print "3. a square"
    print "Enter a number to choose:"
    which_area(raw_input())

print choose_area()

Answer 1

choose_area需要返回一个值。简单计算面积是不够的。

将which_area(raw_input())的最后一行choose_area更改为return which_area(raw_input())。

Answer 2

更改您的代码

which_area(raw_input())

到

which_area(int(raw_input()))

Answer 3

取决于您使用的python版本，原因很少。

由于错误的python版本如果您使用的是python版本3或更高版本。它应该改为
```
which_area(int(input()))
```

或者如果你使用bellow版本到python 3.x那么它应该是（ex-2.7）

   which_area(int(raw_input()))

无论如何要确保使用强制转换，因为你使用输入来取一个数字但是

   raw_input() or input()

函数将输入作为String

因此，根据您的计算，如果您想获得小数，请使用“Float”，如果您想获得哪些数字使用“int”作为演员。

Answer 4

结合以前的答案：

which_area需要一个整数，raw_input()返回一个字符串。你需要：

    which_area(int(raw_input()))

但是，除了triangle_area，circle_area和square_area不返回任何内容之外，他们还会打印一条消息。您可能希望使用以下内容结束这些功能：

    return "The area of your triangle is: " + str(area)

（请注意，我刚刚使用了简单的字符串连接 - 您可以使用旧式或新式字符串格式代替）

Answer 5

函数triangle_area，square_area和circle_area没有返回任何值

def triangle_area():
    print "What is the base length?"
    base = raw_input()
    print "What is the height?"
    height = raw_input()
    area = 0.5*float(base)*float(height)
    print "The area of you triangle is:", area
    return area

def circle_area():
    print "What is the radius of the circle?"
    radius = raw_input()
    area = 3.14159*(float(radius)**2)
    print "The area of your circle is:", area
    return area

def square_area():
    print "What is the length of the side of the square?"
    print "(Remember that squares have equal sides, and if"
    print "you want to enter a seperate length and width"
    print "you have a rectangle.)"
    length = raw_input()
    area = float(length)**2
    print "The area of your square is", area
    return area

def which_area(x):
    if x == 1:
        return triangle_area()
    elif x == 2:
        return circle_area()
    elif x == 3:
        return square_area()
    else:
        return "You didn't pick 1, 2, or 3."

def choose_area():
    print "Calculate the area of which shape?"
    print "1. a triangle"
    print "2. a circle"
    print "3. a square"
    print "Enter a number to choose:"
    which_area(int(raw_input()))

print choose_area()

注意：raw_input将promt作为参数，所以你可以做一些像raw_input（“Height：”）

当我将raw_input（）作为参数时，为什么这个函数不起作用？

5 个答案: