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| Author |
Find indeces of 1's in logical array
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| bobrics 2005-05-31, 9:01 pm |
| Hi,
I have a logical NxM array. How do I find indeces of elements which are
equal to 1?
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| bobrics 2005-05-31, 9:01 pm |
| the reason I want to do this is because I have a logical statement
which returns NxM logical matrix B flagging the values from another
numeric matrix A which I need to do operations on.
I want to update values of A at indeces found from B with new values.
I know that A(B), where B is numeric, will do the job. That's why I
want to find indeces of 1's in my logical B array.
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| Dan Hensley 2005-05-31, 9:01 pm |
| On Tue, 31 May 2005 13:44:14 -0700, bobrics wrote:
> the reason I want to do this is because I have a logical statement
> which returns NxM logical matrix B flagging the values from another
> numeric matrix A which I need to do operations on.
>
> I want to update values of A at indeces found from B with new values.
>
> I know that A(B), where B is numeric, will do the job. That's why I
> want to find indeces of 1's in my logical B array.
Why don't you just use the logical matrix directly? You can.
If you really want the numeric indices, type
help find
Dan
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| per isakson 2005-05-31, 9:01 pm |
| bobrics wrote:
>
>
> the reason I want to do this is because I have a logical statement
> which returns NxM logical matrix B flagging the values from
> another
> numeric matrix A which I need to do operations on.
>
> I want to update values of A at indeces found from B with new
> values.
>
> I know that A(B), where B is numeric, will do the job. That's why I
> want to find indeces of 1's in my logical B array.
>
>
One among many. Probably fast. Surely a bit cryptic. Does it help
you?
[color=darkred]
B =
1 0 1
0 0 1
0 1 0[color=darkred]
A =
117 1 117
3 5 117
4 117 2[color=darkred]
/ per
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| bobrics 2005-05-31, 9:01 pm |
| That helped a lot..
I was doing that before.. but I guess made some mistake...
instead of putting the values at indeces, it just replaced the whole
matrix,,, even though I was using logical vector.
The end result is more important! Thank you guys!
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