[Numpy-discussion] immutable numpy arrays

Robert Kern robert.kern@gmail....
Wed Dec 17 16:24:06 CST 2008

On Wed, Dec 17, 2008 at 15:52, Geoffrey Irving <irving@naml.us> wrote:
> Currently numpy arrays are either writable or unwritable, but
> unwritable arrays can still be changed through other copies.  This
> means that when a numpy array is passed into an interface that
> requires immutability for safety reasons, a copy always has to be
> made.
> One way around this would be to add a NPY_IMMUTABLE flag signifying
> that the contents of the array will never change through other copies.

This is not possible to guarantee. With the __array_interface__, I can
make a numpy array point at any addressable memory without its
knowledge. We can even mutate "immutable" str objects, too.

Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
  -- Umberto Eco

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