User guide

NumPy User Guide, Release 1.9.0
>>> # base points to the view it derived from
>>> v2.base is v1
True
In general, if the array owns its own memory, as for arr in this case, then arr.base will be None - there are some
exceptions to this - see the numpy book for more details.
The base attribute is useful in being able to tell whether we have a view or the original array. This in turn can
be useful if we need to know whether or not to do some specific cleanup when the subclassed array is deleted. For
example, we may only want to do the cleanup if the original array is deleted, but not the views. For an example of how
this can work, have a look at the memmap class in numpy.core.
2.8. Subclassing ndarray 43