[Numpy-discussion] Getting an array's indices when a given condition is true
Lane Brooks
lbrooks at MIT.EDU
Sat Oct 18 23:00:42 EDT 2008
If you want the indexes, check out the np.where command, e.g.
idx = np.where(dat <= limit)
If you want the values, use:
val = dat[dat <= limit]
Lane
Michael wrote:
> Hi list,
>
> been playing around with stride_tricks and find it terrifically
> productive; thankyou to everyone who has worked on this.
>
> I need to filter some data, getting the indices of all entries which are
> less than or equal to 'limit'. How do i best go about that?
>
> Can you enumerate an array using broadcasting?
>
> dat=np.array([ 0. 1.61803399 3.23606798 4.85410197
> 6.47213595
> 8.09016994 9.70820393 11.32623792 12.94427191 14.5623059 1.
> 0.61803399 2.23606798 3.85410197 5.47213595 7.09016994
> 8.70820393 10.32623792 11.94427191 13.5623059 2.
> 0.38196601
> 1.23606798 2.85410197 4.47213595 6.09016994 7.70820393
> 9.32623792 10.94427191 12.5623059 3. 1.38196601
> 0.23606798 1.85410197 3.47213595 5.09016994 6.70820393
> 8.32623792 9.94427191 11.5623059 4. 2.38196601
> 0.76393202 0.85410197 2.47213595 4.09016994 5.70820393
> 7.32623792 8.94427191 10.5623059 5. 3.38196601
> 1.76393202 0.14589803 1.47213595 3.09016994 4.70820393
> 6.32623792 7.94427191 9.5623059 6. 4.38196601
> 2.76393202 1.14589803 0.47213595 2.09016994 3.70820393
> 5.32623792 6.94427191 8.5623059 7. 5.38196601
> 3.76393202 2.14589803 0.52786405 1.09016994 2.70820393
> 4.32623792 5.94427191 7.5623059 8. 6.38196601
> 4.76393202 3.14589803 1.52786405 0.09016994 1.70820393
> 3.32623792 4.94427191 6.5623059 9. 7.38196601
> 5.76393202 4.14589803 2.52786405 0.90983006 0.70820393
> 2.32623792 3.94427191 5.5623059 ])
>
> limit=1.30901699437
>
> for i in dat:
> if i <=limit:
> print i
>
> Michael
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> Numpy-discussion mailing list
> Numpy-discussion at scipy.org
> http://projects.scipy.org/mailman/listinfo/numpy-discussion
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/numpy-discussion/attachments/20081018/cefbc9ce/attachment.html>
More information about the NumPy-Discussion
mailing list