On 2014/05/07 2:14 PM, mfm24 wrote:
I'm having a problem I haven't seen elsewhere (and apologies if it has been answered before).
I see the following behavior (copied verbatim from a python session):
Python 2.7.4 (default, Apr 6 2013, 19:55:15) [MSC v.1500 64 bit (AMD64)] on win32 Type "help", "copyright", "credits" or "license" for more information.
import numpy as np x=[[np.zeros(10)] for i in range(10)] x.index(x[0]) 0 x.index(x[1]) Traceback (most recent call last): File "", line 1, in ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all() x[1].append(np.zeros(10)) x.index(x[1]) 1
Any ideas why I see a ValueError when trying to find the index of a list containing a single ndarray?
In the first example, indexing with 0, it checks the first entry in x, finds that it *is* the target, and so returns the first index, 0. In the second case, indexing with 1, it checks the first entry in x, finds that it is *not* the same object, so it checks to see if it has the same contents. This leads it to compare two ndarrays for equality, which leads to the ValueError. Eric
-Matt ------------------------------------------------------------------------ View this message in context: List of arrays failing index(), remove() etc <http://numpy-discussion.10968.n7.nabble.com/List-of-arrays-failing-index-rem...> Sent from the Numpy-discussion mailing list archive <http://numpy-discussion.10968.n7.nabble.com/> at Nabble.com.
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