[Numpy-discussion] Examples of new (nested) record-types
Travis Oliphant
oliphant at ee.byu.edu
Wed Feb 1 14:17:13 CST 2006
I've just checked in some tests for the nested-record support in numpy.
These tests were written by Francesc Alted and are very useful (they
helped track down at-least two reference-counting errors).
But, a big utility they have is to show a method for defining and
constructing arrays of nested records. Anybody wanting to figure out
how to use that facility in NumPy better would benefit by looking at the
code in
<site-packages>/numpy/core/tests/test_numerictypes.py
in the SVN version of NumPy.
-Travis
P.S. Here is an example of the kind of structure he makes arrays of in
this file...
# This is the structure of the table used for nested objects (DON'T PANIC!):
#
# +-+---------------------------------+-----+----------+-+-+
# |x|Info |color|info |y|z|
# | +-----+--+----------------+----+--+ +----+-----+ | |
# | |value|y2|Info2 |name|z2| |Name|Value| | |
# | | | +----+-----+--+--+ | | | | | | |
# | | | |name|value|y3|z3| | | | | | | |
# +-+-----+--+----+-----+--+--+----+--+-----+----+-----+-+-+
#
After defining an array of these guys you could get at an array of y3
fields using
a['Info']['Info2']['y3']
Or,
reca = a.view(recarray)
reca.Info.Info2.y3
-Travis
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