在 class 中调用一个函数来设置列表的元素

Question

我正在尝试实现我的第一个 class，部分原因是为了打破建模和解决我遇到的数学问题。我认为我的问题与 class 无关，但是...?

错误一直告诉我："NameError: global name 'corner2' is not defined"

我尝试移动函数调用，但它仍然无法识别它，所以我将它放回到我的 init 函数中的列表声明中。

这是我的代码：

class RotatedRectangle(object):

def corner1(a,b):
    a/=2
    b/=2
    x=(a-b)*math.sin(math.pi/4)
    y=(a+b)*math.sin(math.pi/4)
    return (x,y)

def corner2(a,b):
    a/=-2
    b/=2
    x=(a-b)*math.sin(math.pi/4)
    y=(a+b)*math.sin(math.pi/4)
    return (x,y)

def corner3(a,b):
    a/=-2
    b/=-2
    x=(a-b)*math.sin(math.pi/4)
    y=(a+b)*math.sin(math.pi/4)
    return (x,y)

def corner4(a,b):
    a/=2
    b/=2
    x=(a-b)*math.sin(math.pi/4)
    y=(a+b)*math.sin(math.pi/4)
    return (x,y)

def __init__(self, a, b,):
        """Return a Rotated rectangle object whose name is a function of a and b."""
        self.name = str(a) + "," + str(b) + "-rectangle"
        self.corners = [corner1(a,b), corner2(a,b), corner3(a,b), corner4(a,b)]



"""A rectangle with sides equal to even integers a and b is drawn on the          Cartesian plane.Its center (the intersection point of its diagonals) coincides with the point (0, 0),but the sides of the rectangle are not parallel to the axes; instead, they are forming 45 degree angles with the axes.

How many points with integer coordinates are located inside the given   rectangle (including on its sides)? """

Answer 1

你有几个识别错误，忘了加上self参数，应该是：

import math

class RotatedRectangle(object):
  def __init__(self, a, b,):
        """Return a Rotated rectangle object whose name is a function of a and b."""
        self.name = str(a) + "," + str(b) + "-rectangle"
        self.corners = [self.corner1(a,b), self.corner2(a,b), self.corner3(a,b), self.corner4(a,b)]

  def corner1(self,a,b):
      a/=2
      b/=2
      x=(a-b)*math.sin(math.pi/4)
      y=(a+b)*math.sin(math.pi/4)
      return (x,y)

  def corner2(self,a,b):
      a/=-2
      b/=2
      x=(a-b)*math.sin(math.pi/4)
      y=(a+b)*math.sin(math.pi/4)
      return (x,y)

  def corner3(self,a,b):
      a/=-2
      b/=-2
      x=(a-b)*math.sin(math.pi/4)
      y=(a+b)*math.sin(math.pi/4)
      return (x,y)

  def corner4(self,a,b):
      a/=2
      b/=2
      x=(a-b)*math.sin(math.pi/4)
      y=(a+b)*math.sin(math.pi/4)
      return (x,y)

我强烈建议你阅读这个问题和所有答案What is the purpose of self?

Answer 2

在为 Python 中的 class 定义方法时，第一个参数通常设置为 "self"。然后，在调用该方法时，在其前面加上 self.

这是工作代码：

import math

class RotatedRectangle(object):

    def corner1(self,a,b):
        a/=2
        b/=2
        x=(a-b)*math.sin(math.pi/4)
        y=(a+b)*math.sin(math.pi/4)
        return (x,y)

    def corner2(self,a,b):
        a/=-2
        b/=2
        x=(a-b)*math.sin(math.pi/4)
        y=(a+b)*math.sin(math.pi/4)
        return (x,y)

    def corner3(self,a,b):
        a/=-2
        b/=-2
        x=(a-b)*math.sin(math.pi/4)
        y=(a+b)*math.sin(math.pi/4)
        return (x,y)

    def corner4(self,a,b):
        a/=2
        b/=2
        x=(a-b)*math.sin(math.pi/4)
        y=(a+b)*math.sin(math.pi/4)
        return (x,y)

    def __init__(self, a, b,):
            """Return a Rotated rectangle object whose name is a function of a and b."""
            self.name = str(a) + "," + str(b) + "-rectangle"
            self.corners = [self.corner1(a,b), self.corner2(a,b), self.corner3(a,b), self.corner4(a,b)]

Answer 3

您必须使用 self 作为 class 方法的第一个参数
在 class 中调用 class 方法时，您必须将 self 作为其第一个参数传递（以便 class 知道您正在谈论当前对象）

在 class

中定义方法时必须缩进

import math
class RotatedRectangle(object):
    def corner1(self,a,b):
        a/=2
        b/=2
        x=(a-b)*math.sin(math.pi/4)
        y=(a+b)*math.sin(math.pi/4)
        return (x,y)

    def corner2(self,a,b):
        a/=-2
        b/=2
        x=(a-b)*math.sin(math.pi/4)
        y=(a+b)*math.sin(math.pi/4)
        return (x,y)

    def corner3(self,a,b):
        a/=-2
        b/=-2
        x=(a-b)*math.sin(math.pi/4)
        y=(a+b)*math.sin(math.pi/4)
        return (x,y)

    def corner4(self,a,b):
        a/=2
        b/=2
        x=(a-b)*math.sin(math.pi/4)
        y=(a+b)*math.sin(math.pi/4)
        return (x,y)

    def __init__(self, a, b,):
        """Return a Rotated rectangle object whose name is a function of a and b."""
        self.name = str(a) + "," + str(b) + "-rectangle"
        self.corners = [self.corner1(a,b), self.corner2(a,b), self.corner3(a,b), self.corner4(a,b)]

在 class 中调用一个函数来设置列表的元素

Calling a function inside a class to set the element of list

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