[PYTHON MATRIX-SIG] lists vs. tuples

[James Hugunin]

   From: da@maigret.cog.brown.edu (David Ascher)

   Just a thought.

   I believe that most existing python code, when returning collections,
   return tuples.

   The matrix code as implemented returns lists (e.g. shape).  Shape
   strikes me as the kind of thing which might be better off being a tuple
   than a list.  That way people doing:

    a = array(...)
    s = a.shape()
    s[0] = 3

   would be stopped by the interpreter (I'm assuming this isn't working and
   isn't likely to work).

Your code fragment won't work for two reasons.  First, a.shape is a
data member, not a function (this is because you can do a.shape =
new_shape).  And the data member a.shape is a tuple.  You are allowed
to assign to a.shape from any sequence type, but it can only be
accessed as a tuple.

Are you thinking of some other problem?

-Jim

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