# 不知道怎么描述？

111 次浏览

`return self._start.distance_to(self._end)`

`line.start.move_to(2, 1)`

``````"""

Version: 0.1
Author: 骆昊
Date: 2018-03-12
"""

from math import sqrt

class Point(object):

def __init__(self, x=0, y=0):
self._x = x
self._y = y

def move_to(self, x, y):
self._x = x
self._y = y

def move_by(self, dx, dy):
self._x += dx
self._y += dy

def distance_to(self, other):
dx = self._x - other._x
dy = self._y - other._y
return sqrt(dx ** 2 + dy ** 2)

def __str__(self):
return '(%s, %s)' % (str(self._x), str(self._y))

class Line(object):

def __init__(self, start=Point(0, 0), end=Point(0, 0)):
self._start = start
self._end = end

@property
def start(self):
return self._start

@start.setter
def start(self, start):
self._start = start

@property
def end(self):
return self.end

@end.setter
def end(self, end):
self._end = end

@property
def length(self):
return self._start.distance_to(self._end)

if __name__ == '__main__':
p1 = Point(3, 5)
print(p1)
p2 = Point(-2, -1.5)
print(p2)
line = Line(p1, p2)
print(line.length)
line.start.move_to(2, 1)
line.end = Point(1, 2)
print(line.length)``````
2019-09-11 提问
1 个回答

self._start是Point对象，`self._start.distance_to`就是调用Point的distance_to方法。