xoa.misc.get_axis_slices

xoa.misc.get_axis_slices(ndim, axis, **kwargs)[source]

Get standard slices for an axis of a ndim array

Parameters:

ndim – The number of dimensions. It can also be a tuple (like an array shape) or an array.
axis – Index of the axis.

Returns:

A dictionary of tuples of slices. All tuples have a – length of ndim, and can be used has a slice for the array (see exedges =ample).

"all": Select everything.
"first"/"last": First and last.
"firstp1": Second element.
"firstp2": Third element.
"lastm1": Element before the last one.
"lastm2": Second element before the last one.
"firsts": All but the last.
"lasts": All but the first.
"firstsm1": All but the last two.
"lastsp1": All but the first two.
"mid": All but the first and last.

Example

In [1]: var = np.arange(2*5*4).reshape(2, 5, 4)

In [2]: pprint.pprint(get_axis_slices(var, axis=1))
{'all': [slice(None, None, None),
         slice(None, None, None),
         slice(None, None, None)],
 'first': (slice(None, None, None), 0, slice(None, None, None)),
 'firstp1': (slice(None, None, None), 1, slice(None, None, None)),
 'firstp2': (slice(None, None, None), 2, slice(None, None, None)),
 'firsts': (slice(None, None, None),
            slice(0, -1, None),
            slice(None, None, None)),
 'firstsm1': (slice(None, None, None),
              slice(0, -2, None),
              slice(None, None, None)),
 'last': (slice(None, None, None), -1, slice(None, None, None)),
 'lastm1': (slice(None, None, None), -2, slice(None, None, None)),
 'lastm2': (slice(None, None, None), -3, slice(None, None, None)),
 'lasts': (slice(None, None, None),
           slice(1, None, None),
           slice(None, None, None)),
 'lastsp1': (slice(None, None, None),
             slice(2, None, None),
             slice(None, None, None)),
 'mid': (slice(None, None, None), slice(1, -1, None), slice(None, None, None))}