日常笔试积累

def isPointinPolygon(point, rangelist):  #[[0,0],[1,1],[0,1],[0,0]] [1,0.8]
    # 判断是否在外包矩形内，如果不在，直接返回false
    lnglist = []
    latlist = []
    for i in range(len(rangelist)-1):
        lnglist.append(rangelist[i][0])
        latlist.append(rangelist[i][1])
    print(lnglist, latlist)
    maxlng = max(lnglist)
    minlng = min(lnglist)
    maxlat = max(latlist)
    minlat = min(latlist)
    print(maxlng, minlng, maxlat, minlat)
    if (point[0] > maxlng or point[0] < minlng or
        point[1] > maxlat or point[1] < minlat):
        return False
    count = 0
    point1 = rangelist[0]
    for i in range(1, len(rangelist)):
        point2 = rangelist[i]
        # 点与多边形顶点重合
        if (point[0] == point1[0] and point[1] == point1[1]) or (point[0] == point2[0] and point[1] == point2[1]):
            print("在顶点上")
            return False
        # 判断线段两端点是否在射线两侧 不在肯定不相交 射线（-∞，lat）（lng,lat）
        if (point1[1] < point[1] and point2[1] >= point[1]) or (point1[1] >= point[1] and point2[1] < point[1]):
            # 求线段与射线交点 再和lat比较
            point12lng = point2[0] - (point2[1] - point[1]) * (point2[0] - point1[0])/(point2[1] - point1[1])
            print(point12lng)
            # 点在多边形边上
            if (point12lng == point[0]):
                print("点在多边形边上")
                return False
            if (point12lng < point[0]):
                count +=1
        point1 = point2
    print(count)
    if count%2 == 0:
        return False
    else:
        return True


if __name__ == '__main__':
    breadNum=int(input())
    breadlocation=list(map(float,input().split(',')))
    smallNum=int(input())
    smalllocation=list(map(float,input().split(',')))
    rangebread=[[] for i in range(breadNum)]
    point_small=[[] for i in range(smallNum)]
    j=0
    k=0
    for i in range(breadNum):
        rangebread[i].append(breadlocation[j])//这里注意
        rangebread[i].append(breadlocation[j+1])
        j=j+2
    for i in range(smallNum):
        point_small[i].append(smalllocation[k])
        point_small[i].append(smalllocation[k+1])
        k=k+2
    print(rangebread, point_small)
    print(isPointinPolygon(point_small[0], rangebread))

记录一：

问题：判断点是否在多边形内部；

算法来自于网上，这里学到的是python的二维数组输入的方式，也是当时卡住的原因；

来源：https://blog.csdn.net/jq_develop/article/details/44981127