On Wed, Sep 30, 2009 at 2:45 PM, Robert Kern <robert.k...@gmail.com> wrote:
> On Wed, Sep 30, 2009 at 14:40, Gökhan Sever <gokhanse...@gmail.com> wrote: > > Thanks this works. > > > > My second question how to access a second array using this condition? > > > > I am trying slice another array using a compound condition on the > reference > > array. > > > > say: > > > > a = 1,2,3,4,5, > > b = 20,30,40,50,60 > > > > I want to get elements of a only when a = 3,4. I know I need indices but > how > > ? > > Did you mean "elements of b only where a = 3,4"? > > b[(a==3) | (a==4)] > > -- > Robert Kern > > "I have come to believe that the whole world is an enigma, a harmless > enigma that is made terrible by our own mad attempt to interpret it as > though it had an underlying truth." > -- Umberto Eco > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > Ok, ok got it. Thanks Robert :) Following is what I have been looking for exactly. I[1]: a = arange(5) I[2]: b = arange(5)*10 I[3]: a O[3]: array([0, 1, 2, 3, 4]) I[4]: b O[4]: array([ 0, 10, 20, 30, 40]) I[5]: b[(a>1) & (a<3)] O[5]: array([20]) I was forgetting the parenthesis, and consequently I was being bitten by ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all() I am glad that it is not my understanding of logic but the usage of NumPy. -- Gökhan
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