[Numpy-discussion] Index update
Mads Ipsen
madsipsen at gmail.com
Tue Jan 10 15:53:52 EST 2012
Thanks - very cool!
On 10/01/2012 21:45, Val Kalatsky wrote:
>
> A - np.digitize(A, S)
> Should do the trick, just make sure that S is sorted and A and S do
> not overlap,
> if they do remove those items from A using set operations.
> Val
>
> On Tue, Jan 10, 2012 at 2:14 PM, Mads Ipsen <madsipsen at gmail.com
> <mailto:madsipsen at gmail.com>> wrote:
>
> Hi,
>
> Suppose you have N items, say N = 10.
>
> Now a subset of these items are selected given by a list A of
> indices. Lets say that items A = [2,5,7] are selected. Assume now
> that you delete some of the items given by the indices S =
> [1,4,8]. This means that the list of indices A must be updated,
> since items have been deleted. For this particular case the
> updated selection list A becomes A = [1,3,5].
>
> Is there some smart numpy way of doing this index update of the
> selected items in A without looping? Typically N is large.
>
> Best regards,
>
> Mads
>
> --
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+-----------------------------------------------------+
| Mads Ipsen |
+----------------------+------------------------------+
| Gåsebæksvej 7, 4. tv | |
| DK-2500 Valby | phone: +45-29716388 |
| Denmark | email: mads.ipsen at gmail.com |
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