from random import choice
class RandomWalk():
	"""creak a random-walk class"""
	def __init__(self,num_points=5000):
		"""init the attribute of random-walk"""
		self.num_points=num_points
		
		#all random-walk start at (0,0)
		self.x_values=[0]
		self.y_values=[0]
		
	def fill_walk(self):
		"""calculating all poits in random-walk"""
		
		#do random-walk until the list reach the specified length
		while len(self.x_values)<self.num_points:
			#determine the direction and the distance of advance
			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
			
			#refuce to stay in place
			if x_step==0 and y_step==0:
				continue
			
			#calculate the x_value and y_value of next point
			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)
		
		
		
		
		
