On Sun, Apr 4, 2010 at 10:05 AM, Shailendra <shailendra.vi...@gmail.com> wrote: > On Fri, Apr 2, 2010 at 12:34 PM, Shailendra <shailendra.vi...@gmail.com> > wrote: >> Hi All, >> >>>>> x=arange(10) >>>>> indices=[(1,),(2,)] >>>>> x[indices] >> Traceback (most recent call last): >> File "<stdin>", line 1, in <module> >> IndexError: unsupported iterator index
You are using two indices/coordinates in a 1d array >>> np.ravel([(1,),(2,)]) array([1, 2]) >>> np.arange(5)[np.ravel([(1,),(2,)])] array([1, 2]) >>> np.arange(5)[[1,2]] array([1, 2]) >>> np.arange(5)[1,2] Traceback (most recent call last): File "<stdin>", line 1, in <module> IndexError: invalid index >> >> >> But following works. >>>>> x=x.reshape(5,2) >>>>> x >> array([[0, 1], >> [2, 3], >> [4, 5], >> [6, 7], >> [8, 9]]) >>>>> indices=[(1,0),(0,1)] >>>>> x[indices] >> array([2, 1]) I don't know if it is clear in this example: >>> np.arange(10).reshape(5,2)[(1,0,1),(0,1,1)] array([2, 1, 3]) is equivalent to >>> [np.arange(10).reshape(5,2)[i,j] for i,j in zip((1,0,1),(0,1,1))] [2, 1, 3] Josef >> >> >> Should not the first one also work? How to convert [(1,),(2,)] to >> [1,2] efficiently. >> >> Thanks, >> Shailendra >> > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
