#!/usr/bin/env python3.5

from random import choice
import matplotlib.pyplot as plt


class RandomWalk():
	'''
		一个生成随机漫步数据的类
	'''
	def __init__(self, num_points = 5000):
		'''初始化随机漫步属性 '''
		self.num_points = num_points
		#所有的随机漫步都始于（0， 0）
		self.x_values = [0]
		self.y_values = [0]
	def fill_walk(self):
		while len(self.x_values) < self.num_points:
			x_direction = choice([1, -1])
			x_distance = choice([0, 1, 2, 3, 4])
			x_step = x_direction * x_distance
		
			y_direction = choice([1, -1])
			y_distance = choice([0, 1, 2, 3, 4])
			y_step = y_direction * y_distance
			
			#拒绝原地踏步
			if x_step == 0 and y_step == 0:
				continue
			#计算下一个x 和 y的值
			next_x = self.x_values[-1] + x_step
			next_y = self.y_values[-1] + y_step
			
			self.x_values.append(next_x)
			self.y_values.append(next_y)


if __name__ == '__main__':
	rw = RandomWalk()
	rw.fill_walk()
	plt.scatter(rw.x_values, rw.y_values, s = 15)
	plt.show()






