[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





More information about the Numpy-discussion mailing list