Question

Python noob在这里。我正在尝试添加一组在'if'语句中定义的输入变量，每当我尝试查找总和时，它只会显示内联值。例如，当a，b，c和d等于5时，周长= 555 ......

shape = raw_input("Is the plot a (q) quadrilateral or (t) triangle?")
if shape.lower() == "q":
    a = raw_input("What is the length in feet of side 'a'?")
    b = raw_input("What is the length in feet of side 'b'?")
    c = raw_input("What is the length in feet of side 'c'?")
    d = raw_input("What is the length in feet of side 'd'?")
elif shape.lower() == "t":
    a = raw_input("What is the length in feet of side 'a'?")
    b = raw_input("What is the length in feet of side 'b'?")
    c = raw_input("What is the length in feet of side 'c'?")
else:
    print "Please enter 'q' for quadrilateral or 't' for triangle."

if shape.lower() == "q":
    perimeter = a + b + c + d
elif shape.lower() == "t":
    perimeter = a + b + c
else:
    print "Please make sure you enter numbers only."

print perimeter

Answer 1

str值可以像数字一样相互添加。您使用的+运算符工作正常，但连接字符串的值。 raw_input的结果是一个字符串（str），这就是为什么你会看到'555'而不是15。为了对数字进行求和，使用int()来强制赋值添加之前的数字：

try:
    a = int(raw_input('gimme a number'))
except ValueError as e
    print 'that was not a number, son'

Answer 2

确保您的raw_input实际上是一个int（）：

shape = raw_input("Is the plot a (q) quadrilateral or (t) triangle?")
if shape.lower() == "q":
    try:
        a = raw_input("What is the length in feet of side 'a'?")
        b = raw_input("What is the length in feet of side 'b'?")
        c = raw_input("What is the length in feet of side 'c'?")
        d = raw_input("What is the length in feet of side 'd'?")
        perimeter = int(a) + int(b) + int(c) + int(d)
    except ErrorValue as e  
        print "Please make sure you enter numbers only."

elif shape.lower() == "t":
    try:
        a = raw_input("What is the length in feet of side 'a'?")
        b = raw_input("What is the length in feet of side 'b'?")
        c = raw_input("What is the length in feet of side '
        perimeter = int(a) + int(b) + int(c)
    except ErrorValue as e  
        print "Please make sure you enter numbers only."
else:
    print "Please enter 'q' for quadrilateral or 't' for triangle."

Answer 3

对于变量a，b，c和d，请使用input(prompt)代替raw_input(prompt)。 raw_input返回一个字符串，但是input返回被评估为python文字的控制台输入。（截至目前，你是连接字符串，而不是添加整数。）

Answer 4

您的代码不是一个好设计。如果您想添加更多形状，六边形，八边形等，该怎么办？实际上，您可以使用dict将形状映射存储到边数。您不必为每个形状编写多个if语句。你将不得不做更少的类型检查，你可以使用python内置函数sum来返回参数。继续，继续尝试以下内容：

d = {'q': 4, 't': 3}

shape = raw_input("Is the plot a (q) quadrilateral or (t) triangle?\n")

if shape.lower() not in d:
    print "Please enter 'q' for quadrilateral or 't' for triangle."

else:
    sides = []

    for i in range(0,d.get(shape.lower())):
        side = raw_input("What is the length in feet of side " + str(i+1))
        try:
            sides.append(int(side))
        except ValueError:
            print "Integer value only"

    print sum(sides)

Answer 5

我是用字典做的。

sides = {'a':0,'b': 0,'c': 0,'d': 0}
perimeter = 0

shape = raw_input("Is the plot a (q) quadrilatral or (t) triangle?: ")
if shape.lower() == "q":
    for side, length in sides.iteritems():
        sides[side] = input("What is the length (in feet) of side %s?: " % side)
        perimeter+=int(sides[side])

elif shape.lower() == "t":
    sides.pop("d",None)
    for side, length in sides.iteritems():
        sides[side] = input("What is the length (in feet) of side %s?: " % side)
        perimeter+=int(sides[side])
else:
    print "Please enter 'q' or 't'."

print "Perimeter is: %d" % perimeter

我认为字典会更容易使用。可能会更清洁，而不是重复自己。

如何在Python中添加变量？

5 个答案: