The rationale for the change allowing that construction was twofold: it's easier to understand what has gone wrong when seeing the `list`s in the repr than it was from the cryptic error message; and there were some jagged cases that already succeeded in this way, and it was less confusing to be consistent.
I agree that the behavior is not terribly useful, and object arrays constructed containing lists are quite possibly something we should warn about. Eric On Thu, Dec 27, 2018, 2:22 AM Benjamin Root <ben.v.r...@gmail.com wrote: > Ewww, kinda wish that would be an error... It would be too easy for a typo > to get accepted this way. > > On Wed, Dec 26, 2018 at 1:59 AM Eric Wieser <wieser.eric+nu...@gmail.com> > wrote: > >> In the latest version of numpy, this runs without an error, although may >> or may not be what you want: >> >> In [1]: np.array([[1,2],[[1,2],[3,4]]]) >> Out[1]: >> array([[1, 2], >> [list([1, 2]), list([3, 4])]], dtype=object) >> >> Here the result is a 2x2 array, where some elements are numbers and >> others are lists. >> >> >> On Wed, 26 Dec 2018 at 06:23 Mark Alexander Mikofski < >> mikof...@berkeley.edu> wrote: >> >>> I believe numpy arrays must be rectangular, yours is jagged, instead try >>> >>> >>> x3d = np.array([[[1, 2], [1, 2], [3, 4]]]) >>> >>> x3d.shape >>> (1, 3, 2) >>> >>> Note: 3 opening brackets, yours has 2 >>> And single brackets around the 3 innermost arrays, yours has single >>> brackets for the 1st, and double brackets around the 2nd and 3rd >>> >>> >>> On Tue, Dec 25, 2018, 6:20 PM Jeff <je...@vodafonemail.de wrote: >>> >>>> hello, >>>> >>>> sorry newbe to numpy. >>>> >>>> I want to define a three-dim array. >>>> I know this works: >>>> >>>> >>> np.array([[[1,2],[3,4]],[[5,6],[7,8]]]) >>>> array([[[1, 2], >>>> [3, 4]], >>>> >>>> [[5, 6], >>>> [7, 8]]]) >>>> >>>> But can you tell why this doesnt work? >>>> >>>> >>> np.array([[1,2],[[1,2],[3,4]]]) >>>> Traceback (most recent call last): >>>> File "<stdin>", line 1, in <module> >>>> ValueError: setting an array element with a sequence. >>>> >>>> >>>> Thank you. >>>> _______________________________________________ >>>> NumPy-Discussion mailing list >>>> NumPy-Discussion@python.org >>>> https://mail.python.org/mailman/listinfo/numpy-discussion >>>> >>> _______________________________________________ >>> NumPy-Discussion mailing list >>> NumPy-Discussion@python.org >>> https://mail.python.org/mailman/listinfo/numpy-discussion >>> >> _______________________________________________ >> NumPy-Discussion mailing list >> NumPy-Discussion@python.org >> https://mail.python.org/mailman/listinfo/numpy-discussion >> > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@python.org > https://mail.python.org/mailman/listinfo/numpy-discussion >
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