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Assiging to structured array rows with list/array fails (Trac #1758) #2353
Description
Original ticket http://projects.scipy.org/numpy/ticket/1758 on 2011-03-07 by @rgommers, assigned to unknown.
Assigning to a structured array with a tuple works, with a list results in an error. Would be good if this could be made to work (this is an enhancement request). With an array gives no warning or exception, but results in garbage. This is a bug.
See also http://thread.gmane.org/gmane.comp.python.numeric.general/30793/focus=30793
>>> arr = np.zeros((5,), dtype=[('var1','f8'),('var2','f8')])
>>> arr['var1'] = np.arange(5)
>>> arr
array([(0.0, 0.0), (1.0, 0.0), (2.0, 0.0), (3.0, 0.0), (4.0, 0.0)],
dtype=[('var1', '<f8'), ('var2', '<f8')])
>>> arr[0] = (10,20)
>>> arr
array([(10.0, 20.0), (1.0, 0.0), (2.0, 0.0), (3.0, 0.0), (4.0, 0.0)],
dtype=[('var1', '<f8'), ('var2', '<f8')])
>>> arr[0] = np.array([10,20])
>>> arr
array([(4.2439915824246103e-313, 0.0), (1.0, 0.0), (2.0, 0.0), (3.0, 0.0),
(4.0, 0.0)],
dtype=[('var1', '<f8'), ('var2', '<f8')])
If this is fixed, please update doc/structured_arrays.py (section "Filling structured arrays").
Activity
numpy-gitbot commentedon Oct 19, 2012
@rgommers wrote on 2011-03-09
For the array assignment part, it does work when no casting has to be done. From Skipper on-list:
Still a bug, since casting elements of a tuple works fine.
charris commentedon Feb 20, 2014
Still fails 1.9-devel.
MAINT: improve struct assignment, allow multi fields views
MAINT: improve struct assignment, allow multi fields views