我试图了解类和函数，但似乎无法弄清楚我的代码出了什么问题

Question

Calculating the area of a triangle

class area:

    def traingle(self,height,length):
        self.height=height
        self.length=length

    def calculate(self,maths):
        self.maths= (self.height)*(self.length)*(0.5)

    def answer(self):
        print 'Hello, the aswer is %i'%self.maths

first= area()

first.traingle(4,5)

first.calculate

print first.answer

Answer 1

What about this?

import math


class Triangle:

    def __init__(self, height, length):
        self.height = height
        self.length = length

    def calculate(self):
        return (self.height) * (self.length) * (0.5)

    def answer(self):
        print 'Hello, the aswer is %.2f' % self.calculate()

first = Triangle(4, 5)
first.answer()

Remember, to call a method you need to use parenthesis, when you're doing first.answer you're not executing your method, instead you should be doing first.answer()

Another different solution for this type of problem could be something like this:

import math


class Triangle:

    def __init__(self, height, length):
        self.height = height
        self.length = length

    def area(self):
        return (self.height) * (self.length) * (0.5)


class Quad:

    def __init__(self, width, height):
        self.width = width
        self.height = height

    def area(self):
        return self.width * self.height


for index, obj in enumerate([Triangle(4, 5), Quad(2, 3)]):
    print 'Area for {0} {1} = {2:.2f}'.format(obj.__class__, index, obj.area())

In any case, make sure you go through some of the available python tutorials out there in order to understand all the concepts first ;-)