[PYTHON MATRIX-SIG] flattened array indexing

Chris Chase S1A chris.chase@jhuapl.edu
Mon, 13 Nov 1995 18:12:44 -0500

I had suggested before that the "[]" syntax support both
multi-dimensional product indexing and flattened array indexing.
However, with the proposed

M[i,j] <-> M[(i,j)]

trying to also implement flattened indexing with the same syntax could
cause some problems.  Instead it might be better to have a separate
M.flat(i) method for flattened indexing.

I would then assume when i is a scalar M[i] is "hierarchical" indexing
like Jim Fulton has suggested (i.e. M[i] returns a one lower
dimensional array)

I assume that if M has 3 dimensions then M[1,2] would be an error for
not specifying the correct number of indexes.  A question:

M 1-dimensional.  
i = (1,2,3)

Is the following a "wrong number of indexes" error or will 1D arrays
be treated differently?

M[i] <-> M[(1,2,3)] 

Would one have to resort to:

M[(i,)] <-> M[((1,2,3))] ?

Chris Chase

MATRIX-SIG  - SIG on Matrix Math for Python

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