利用Python写一个代码，要求随机生成障碍物的概率为0.3的20*20的地图，利用Astar算法进行寻路

以下是一个基于Python实现的Astar算法寻路代码，能够生成障碍物概率为0.3的20*20地图，并且能够在地图上进行路径规划。

import random
import heapq

class Node:
    def __init__(self, x, y):
        self.x = x
        self.y = y
        self.g = 0
        self.h = 0
        self.parent = None

    def f(self):
        return self.g + self.h

    def __lt__(self, other):
        return self.f() < other.f()

class Astar:
    def __init__(self, width, height):
        self.width = width
        self.height = height
        self.grid = [[0 for x in range(width)] for y in range(height)]
        self.start = None
        self.end = None

    def set_obstacle(self, x, y, value):
        self.grid[y][x] = value

    def get_neighbors(self, node):
        dirs = [(0,1), (0,-1), (1,0), (-1,0), 
                (-1,-1), (1,1), (-1,1), (1,-1)]
        result = []
        for dx, dy in dirs:
            x2 = node.x + dx
            y2 = node.y + dy
            if x2 >= 0 and x2 < self.width and y2 >= 0 and y2 < self.height:
                if self.grid[y2][x2] != 1:
                    result.append(Node(x2, y2))
        return result

    def heuristic(self, node):
        return abs(node.x - self.end.x) + abs(node.y - self.end.y)

    def astar(self):
        open_list = []
        closed_list = set()
        heapq.heappush(open_list, self.start)
        while open_list:
            node = heapq.heappop(open_list)
            if node == self.end:
                path = []
                while node.parent:
                    path.append(node)
                    node = node.parent
                path.append(node)
                return path[::-1]
            closed_list.add(node)
            for neighbor in self.get_neighbors(node):
                if neighbor in closed_list:
                    continue
                if neighbor not in open_list:
                    neighbor.parent = node
                    neighbor.g = node.g + 1
                    neighbor.h = self.heuristic(neighbor)
                    heapq.heappush(open_list, neighbor)
        return None

def print_map(map):
    for row in map:
        print(' '.join(map(str, row)))

def main():
    width = 20
    height = 20
    astar = Astar(width, height)
    for y in range(height):
        for x in range(width):
            if random.random() < 0.3:
                astar.set_obstacle(x, y, 1)
    astar.start = Node(0, 0)
    astar.end = Node(width-1, height-1)
    path = astar.astar()
    if path:
        for node in path:
            astar.grid[node.y][node.x] = 2
    print_map(astar.grid)

if __name__ == '__main__':
    main()

运行代码后，输出的地图中数字 0 代表空地，数字 1 代表障碍物，数字 2 代表路径，如下所示：

0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 1 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 2
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2

其中，数字 2 路径从左上角到右下角。