首页 > 遍历python不定常不定维数组

遍历python不定常不定维数组

有一大推geojson数据,现在需要对其进行坐标转换,geojson数据示例

coordinates = [119,35]
coordinates = [[119,35],[119,35]]
coordinates = [[[119,35],[119,35]],[[119,35],[119,35]]]

期望转换后的坐标:

coordinates = [11900,3500]
coordinates = [[11900,3500],[11900,3500]]
coordinates = [[[11900,3500],[11900,3500]],[[11900,3500],[11900,3500]]]

怎么遍历到每一个position(坐标对)?

我现在是这么做的:

def transform(x,y,other_parameter):
    return ....


def miterator(ary,mapper):
    if isinstance(ary,list):
        if isinstance(ary[0],list):
            for el in ary:
                miterator(el, mapper)
        else:
            ary[0],ary[1] = mapper(ary[0],ary[1])

def logic(...):
    other_parameter= ....
    coordinates = get_coordinates(..)
    miterator(coordinates,transform) #??????

然后问题就出来了,我怎么把other_parameter传到transform里面?


所以 我希望最好通过generator方式:

def xgenerator(ary):
    if xx:
        ...
    yield(x,y)

然后我就可以通过这种方式调用:

def logic(...):
    other_parameter= ....
    coordinates = get_coordinates(..)
    for x,y in xgenerator(coordinates):
        transform(x,y,other_parameter)

但是这个generator我死活写不出来,怎么破?


很早之前在OSC上留过一个

def dft(tree):
        try:
                for c in tree:
                        for e in dft(c):
                                yield e
        except TypeError:
                pass
        yield tree

http://www.oschina.net/code/snippet_724613_13019


这样?

#!/usr/bin/env python3

def convert(L):
  ret = []
  for x in L:
    if isinstance(x, (int, float)):
      ret.append(x * 100)
    else:
      ret.append(convert(x))
  return ret

if __name__ == '__main__':
  a = [119,35]
  b = [[119,35],[119,35]]
  c = [[[119,35],[119,35]],[[119,35],[119,35]]]
  print(convert(a))
  print(convert(b))
  print(convert(c))

把坐标一个个地 yield 出来的版本:

def convert(L):
  if isinstance(L[0], (int, float)):
    yield L
  else:
    for x in L:
      yield from convert(x)

Python 3.2 及以下:

def convert(L):
  if isinstance(L[0], (int, float)):
    yield L
  else:
    for x in L:
      for y in convert(x):
        yield y

这个递归很难写?不过估计Python除了递归应该有更好的方法吧,我也不太懂。顺带帮你把所有的坐标从序列改成元组格式了。仅供参考:

#!/usr/bin/env python3

def transform(el, args):
    return (el[0]*args[0], el[1]*args[0])

def miterator(arrs, mapper, *args):
    if isinstance(arrs[0],int):
        return mapper(arrs, args[0])

    arr = [];
    for el in arrs:
        if isinstance(el[0], int): item = mapper(el, args[0])
        else: item = miterator(el, mapper, args)
        arr.append(item)
    return arr

coordinates = [[[119,35],[119,35]],[[119,35],[119,35]]]
print(miterator(coordinates, transform, 100))
# [[(11900, 3500), (11900, 3500)], [(11900, 3500), (11900, 3500)]]
【热门文章】
【热门文章】