[PYTHON MATRIX-SIG] Pseudo Indices

Chris Chase S1A chris.chase@jhuapl.edu
Tue, 30 Jan 1996 17:53:56 -0500

>> a[RubberIndex, 3].

Guido> You could sneak this into the abovementioned patch as "a[::, 3]".

Actually, All is equivalent to "::" and it corresponds to the nil
index syntax of Yorick (which is indicated by whitespace between the
commas) and the * index syntax of Matlab or IDL.

Rubber indexes are different.  Yorick has two types of rubber indexes,
one has syntax "*" and the other is ".." and neither type has the same
behavior as "::".  Both types act as if the entire length of the
missing intervening dimensions were selected.  "*" collapses the
missing intervening dimensions into 1 dimension.  ".." does not
collapse the intervening dimensions (it is like using All for the
missing dimensions).

Currently the Numeric module RubberIndex is like the Yorick ".."
rubber index.  I imagine that the collapsing type rubber index could
easily be added by applying a shape change to the current RubberIndex
behavior.  What would be a possible name for this type of rubber
index?  CollapseIndex?


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