def flatnotmasked_edges(a):
"""Finds the indices of the first and last not masked values in a 1D masked array.
If all values are masked, returns None.
"""
m = getmask(a)
if m is nomask or not numpy.any(m):
return [0,-1]
unmasked = numeric.flatnonzero(~m)
if len(unmasked) > 0:
return unmasked[[0,-1]]
else:
return None
def flatnotmasked_contiguous(a):
"""Finds contiguous unmasked data in a flattened masked array.
Returns a sorted sequence of slices (start index, end index).
"""
m = getmask(a)
if m is nomask:
return (a.size, [0,-1])
unmasked = numeric.flatnonzero(~m)
if len(unmasked) == 0:
return None
result = []
for k, group in groupby(enumerate(unmasked), lambda (i,x):i-x):
tmp = numpy.fromiter((g[1] for g in group), int_)
# result.append((tmp.size, tuple(tmp[[0,-1]])))
result.append( slice(tmp[0],tmp[-1]) )
