Le vendredi 14 octobre 2011 à 08:04 -0400, Neal Becker a écrit : > suppose I have: > > In [10]: u > Out[10]: > array([[0, 1, 2, 3, 4], > [5, 6, 7, 8, 9]]) > > And I have a vector v: > v = np.array ((0,1,0,1,0)) > > I want to form an output vector which selects items from u where v is the > index > of the row of u to be selected. > > In the above example, I want: > > w = [0,6,2,8,4] > > I can't seem to find a syntax that does this. > > Now, more importantly, I need the result to be a reference to the original > array > (not a copy), because I'm going to use it on the LHS of an assignment. Is > this > possible?
What about np.where? http://docs.scipy.org/doc/numpy/reference/generated/numpy.where.html w = np.where(v, u[1], u[0]) if you may want to have more than two options (more than two lines for u), then np.choose may be more appropriate http://docs.scipy.org/doc/numpy/reference/generated/numpy.choose.html -- Fabrice Silva _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion