B q\@s$ddlmZdgZGdddZdS))logNDSlicingMixinc@s8eZdZdZddZddZddZdd Zd d Zd S) raMixin to provide slicing on objects using the `NDData` interface. The ``data``, ``mask``, ``uncertainty`` and ``wcs`` will be sliced, if set and sliceable. The ``unit`` and ``meta`` will be untouched. The return will be a reference and not a copy, if possible. Examples -------- Using this Mixin with `~astropy.nddata.NDData`: >>> from astropy.nddata import NDData, NDSlicingMixin >>> class NDDataSliceable(NDSlicingMixin, NDData): ... pass Slicing an instance containing data:: >>> nd = NDDataSliceable([1,2,3,4,5]) >>> nd[1:3] NDDataSliceable([2, 3]) Also the other attributes are sliced for example the ``mask``:: >>> import numpy as np >>> mask = np.array([True, False, True, True, False]) >>> nd2 = NDDataSliceable(nd, mask=mask) >>> nd2slc = nd2[1:3] >>> nd2slc[nd2slc.mask] NDDataSliceable([3]) Be aware that changing values of the sliced instance will change the values of the original:: >>> nd3 = nd2[1:3] >>> nd3.data[0] = 100 >>> nd2 NDDataSliceable([ 1, 100, 3, 4, 5]) See also -------- NDDataRef NDDataArray cCs*|jjdkrtd||}|jf|S)Nzscalars cannot be sliced.)datashape TypeError_slice __class__)selfitemkwargsrr>lib/python3.7/site-packages/astropy/nddata/mixins/ndslicing.py __getitem__6s  zNDSlicingMixin.__getitem__cCsTi}|j||d<|||d<|||d<|||d<|j|d<|j|d<|S)aCollects the sliced attributes and passes them back as `dict`. It passes uncertainty, mask and wcs to their appropriate ``_slice_*`` method, while ``meta`` and ``unit`` are simply taken from the original. The data is assumed to be sliceable and is sliced directly. When possible the return should *not* be a copy of the data but a reference. Parameters ---------- item : slice The slice passed to ``__getitem__``. Returns ------- dict : Containing all the attributes after slicing - ready to use them to create ``self.__class__.__init__(**kwargs)`` in ``__getitem__``. r uncertaintymaskwcsunitmeta)r_slice_uncertainty _slice_mask _slice_wcsrr)r r r rrr r?s  zNDSlicingMixin._slicecCs>|jdkrdSy |j|Stk r6tdYnX|jS)Nzuncertainty cannot be sliced.)rrrinfo)r r rrr r`s  z!NDSlicingMixin._slice_uncertaintycCs>|jdkrdSy |j|Stk r6tdYnX|jS)Nzmask cannot be sliced.)rrrr)r r rrr rks  zNDSlicingMixin._slice_maskcCs>|jdkrdSy |j|Stk r6tdYnX|jS)Nzwcs cannot be sliced.)rrrr)r r rrr rts  zNDSlicingMixin._slice_wcsN) __name__ __module__ __qualname____doc__rrrrrrrrr r s + !  N)Zastropyr__all__rrrrr s