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From: Bruce Bowler on 19 Jul 2010 13:51
I would have thought this little snippet would have worked to set a
subset of an array to nan, but it didn't... I know I can do it with a
loop, but is there a "better way"?

array(abs(array(:,3:11))>threshold,3:11) = nan;

Basically if the absolute value of an element in columns 3 thru 11 is
greather than some threshold, set it to nan.

Thanks!
Bruce

--
+-------------------+---------------------------------------------------+

Bruce Bowler | No man has a good enough memory to make a

1.207.633.9610 | successful liar.

bbowler(a)bigelow.org | - Abraham Lincoln

+-------------------+---------------------------------------------------+

From: Wayne King on 19 Jul 2010 14:06
Bruce Bowler <bbowler(a)bigelow.org> wrote in message <8ajhl6F7b3U1(a)mid.individual.net>...
> I would have thought this little snippet would have worked to set a
> subset of an array to nan, but it didn't... I know I can do it with a
> loop, but is there a "better way"?
>
> array(abs(array(:,3:11))>threshold,3:11) = nan;
>
> Basically if the absolute value of an element in columns 3 thru 11 is
> greather than some threshold, set it to nan.
>
> Thanks!
> Bruce
>
> --
> +-------------------+---------------------------------------------------+
> Bruce Bowler | No man has a good enough memory to make a
> 1.207.633.9610 | successful liar.
> bbowler(a)bigelow.org | - Abraham Lincoln
> +-------------------+---------------------------------------------------+

Hi Bruce, one of many ways.

A = randn(10,12);
B = A(:,3:11);
Thresh = 1.5;
B(abs(B)>1.5) = NaN;
A(:,3:11) = B;

Wayne
From: Sean on 19 Jul 2010 14:18
Bruce Bowler <bbowler(a)bigelow.org> wrote in message <8ajhl6F7b3U1(a)mid.individual.net>...
> I would have thought this little snippet would have worked to set a
> subset of an array to nan, but it didn't... I know I can do it with a
> loop, but is there a "better way"?
>
> array(abs(array(:,3:11))>threshold,3:11) = nan;
>
> Basically if the absolute value of an element in columns 3 thru 11 is
> greather than some threshold, set it to nan.

> 1.207

To a fellow Mainer!
One way:

array = magic(20);
threshold = 30;
start_col = 3;
end_col = 11;
idx = find(abs(array(:,start_col:end_col))>threshold)+(start_col-1)*size(array,1); %convert local idx to global idx with addition at end
array(idx) = nan;
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