On Mon, Jan 10, 2011 at 12:15, Nils Becker <n.becker@amolf.nl> wrote:

Robert,

your answer does work: after indexing with () I can then further index into the datatype.

In [115]: a_rank_0[()][0] Out[115]: 0.0

I guess I just found the fact confusing that a_rank_1[0] and a_rank_0 compare and print equal but behave differently under indexing.

They do not print equal. Many things compare equal but do not behave the same.

More precisely if I do In [117]: b = a_rank_1[0]

then

In [118]: b.shape Out[118]: ()

and

In [120]: a_rank_0 == b Out[120]: True

but

In [119]: b[0] Out[119]: 0.0

works but a_rank_0[0] doesn't. I thought b is a rank-0 array which it apparently is not since it can be indexed. So maybe b[0] should fail for consistency?

No, b is a record scalar. It can be indexed because it is often convient to treat such records like tuples. This replaces the default indexing behavior of scalars (which is to simply disallow indexing). a_rank_0 is an array, so the array indexing semantics are the default, and we do not change them. -- 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