每秒出现一次未知元素后拆分字符串

Question

我有一个字符串，其中包含代表多边形的坐标列表。在这个列表中，每个多边形都有相同的起始和结束坐标。我需要将每个多边形放在单独的字符串（或列表）中。' 17.17165756225586 -28.102264404296875，17.184370040893555 -28.200496673583984,17.1986083984375 -28.223613739013672，17.17165756225586 -28.102264404296875， 28.865726470947266 -28.761619567871094，28.80694007873535 -28.75750160217285,28.792499542236328 -28.706947326660156，28.865726470947266 -28.761619567871094 '所以从这个简单的例子中，我需要有两个元素：一个= ' 17.17165756225586 -28.102264404296875，17.184370040893555 -28.200496673583984,17.1986083984375 -28.223613739013672，17.17165756225586 -28.102264404296875 '两= ' 28.865726470947266 -28.761619567871094，28.80694007873535 -28.75750160217285,28.792499542236328 -28.706947326660156，28.865726470947266 -28.761619567871094 ' *字符串中可以有更多的多边形，每个多边形都需要分开。我只能为此使用标准的 python 库

Answer 1

由于您的输入已经是一个字符串（而且您的预期结果也是？），您可以使用带有反向引用的正则表达式 来尝试这个超级懒惰的解决方案(([^,]+).*\2)。这里，[^,]+是第一个坐标对，.*其他对，\2再次是第一对。

>>> s = '17.17165756225586 -28.102264404296875,17.184370040893555 -28.200496673583984,17.1986083984375 -28.223613739013672,17.17165756225586 -28.102264404296875, 28.865726470947266 -28.761619567871094,28.80694007873535 -28.75750160217285,28.792499542236328 -28.706947326660156, 28.865726470947266 -28.761619567871094'

>>> re.findall(r"(([^,]+).*\2)", s)

[('17.17165756225586 -28.102264404296875,17.184370040893555 -28.200496673583984,17.1986083984375 -28.223613739013672,17.17165756225586 -28.102264404296875',

  '17.17165756225586 -28.102264404296875'),

 (' 28.865726470947266 -28.761619567871094,28.80694007873535 -28.75750160217285,28.792499542236328 -28.706947326660156, 28.865726470947266 -28.761619567871094',

  ' 28.865726470947266 -28.761619567871094')]

或者使用finditer并获取group直接获取字符串列表：

>>> [m.group() for m in re.finditer(r"(([^,]+).*\2)", s)]

['17.17165756225586 -28.102264404296875,17.184370040893555 -28.200496673583984,17.1986083984375 -28.223613739013672,17.17165756225586 -28.102264404296875',

 ' 28.865726470947266 -28.761619567871094,28.80694007873535 -28.75750160217285,28.792499542236328 -28.706947326660156, 28.865726470947266 -28.761619567871094']

一些后期处理后，获得对数字的实际列表（与_作为的结果findall;对于finditer删除[0]）：

>>> [[tuple(map(float, y.split())) for y in x[0].split(",")] for x in _]

[[(17.17165756225586, -28.102264404296875),

  (17.184370040893555, -28.200496673583984),

  (17.1986083984375, -28.223613739013672),

  (17.17165756225586, -28.102264404296875)],

 [(28.865726470947266, -28.761619567871094),

  (28.80694007873535, -28.75750160217285),

  (28.792499542236328, -28.706947326660156),

  (28.865726470947266, -28.761619567871094)]]

对于更长的字符串，这可能不是最快的解决方案，不过我没有计时。

Answer 2

s='17.17165756225586 -28.102264404296875,17.184370040893555 -28.200496673583984,17.1986083984375 -28.223613739013672,17.17165756225586 -28.102264404296875, 28.865726470947266 -28.761619567871094,28.80694007873535 -28.75750160217285,28.792499542236328 -28.706947326660156, 28.865726470947266 -28.761619567871094'

#convert the input in a list of points 

coordinates = [tuple(map(float,el.split())) for el in s.split(",")]

polygons = []

#find the polygons

while coordinates:

    ind = coordinates[1:].index(coordinates[0]) 

    polygons.append(coordinates[0:ind+2])

    coordinates = coordinates[ind+2:]

#output

[(17.17165756225586, -28.102264404296875), (17.184370040893555, -28.200496673583984), (17.1986083984375, -28.223613739013672), (17.17165756225586, -28.102264404296875)]

[(28.865726470947266, -28.761619567871094), (28.80694007873535, -28.75750160217285), (28.792499542236328, -28.706947326660156), (28.865726470947266, -28.761619567871094)]

Answer 3

这是一个相当丑陋但有效的解决方案，只是将明显的方法真正放入代码中。

# Note that your string has inconsistent separators -- sometimes ',', sometimes ', '.

# I'm going to separate on `,` and not worry about it -- you need to work out

# what the correct separator is.

s = '17.17165756225586 -28.102264404296875,17.184370040893555 -28.200496673583984,17.1986083984375 -28.223613739013672,17.17165756225586 -28.102264404296875, 28.865726470947266 -28.761619567871094,28.80694007873535 -28.75750160217285,28.792499542236328 -28.706947326660156, 28.865726470947266 -28.761619567871094'

coordinates = s.split(',')

polygon = []

polygons = []

new = True

for coordinate in coordinates:

    polygon.append(coordinate)

    if new:

        start = coordinate

        new = False

    elif coordinate == start:

        polygons.append(polygon)

        polygon = []

        new = True

result = [",".join(polygon) for polygon in polygons]

print(result)

Out:

['17.17165756225586 -28.102264404296875,17.184370040893555 -28.200496673583984,17.1986083984375 -28.223613739013672,17.17165756225586 -28.102264404296875', ' 28.865726470947266 -28.761619567871094,28.80694007873535 -28.75750160217285,28.792499542236328 -28.706947326660156, 28.865726470947266 -28.761619567871094']