python - 如何简化函数以查明字符串是否包含描述多边形的坐标？

Question

我有以下字符串:

points = "34.09352 -118.27483, 34.0914 -118.2758, 34.082 -118.2782, 34.0937 -118.2769, 34.0933 -118.2748"

points 是一个包含以逗号分隔的坐标值(纬度和经度)的字符串。

我想检查这个字符串是否仅包含整数或浮点值，以及第一个坐标是否等于最后一个。

我有以下代码:

def validate_points(points):
   coordinates = points.split(',')

   for point in coordinates:
      latlon = point.split(' ')

      latitude = latlon[0]
      longitude = latlon[1]
      if not is_number(latitude) or not is_number(longitude):
         raise WrongRequestDataError("Please, specify the correct type of points value. It must be a numeric value")

   first = coordinates[0]
   last = coordinates[len(coordinates) - 1]
   if first != last:
        raise WrongRequestDataError("Incorrect points format, the first point must be equal to last")

def is_number(s):
   try:
     if float(s) or int(s):
        return True
   except ValueError:
        return False

有什么方法可以简化或加速这段代码吗？

Answer 1

您的输入几乎看起来像 WKT polygon .

使用 shapely根据 Python 的 "Easier to ask for forgiveness than permission"，您可以简单地尝试将这些点解析为 WKT，看看会发生什么。原理:

# pip install shapely
from shapely import wkt

def is_well_defined_polygon(points):
    try:
        wkt.loads("POLYGON((%s))" % points)
        return True
    except:
        return False

points = "34.09352 -118.27483, 34.0914 -118.2758, 34.082 -118.2782, 34.0937 -118.2769, 34.0933 -118.2748, 34.09352 -118.27483"

print(is_well_defined_polygon(points))
# True
print(is_well_defined_polygon("1 2, 3 4"))
# IllegalArgumentException: Points of LinearRing do not form a closed linestring
# False
print(is_well_defined_polygon("a b c d"))
# ParseException: Expected number but encountered word: 'a'
# False