make true statements return value that it is associated with
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So I'm basically trying to get the values of the intersects of 2 matrices in the same position on the matrix they were previously. I'm trying to do this with a huge 350 row data set that has 4 columns. I already have a for loop to set up for the intersect values as well as using ismember function to know whether there is a duplicate that exist in a certain position. here's what comes out of both values.
O(1,:) = 12.7 0 0 0
L(1,:) = 0 1 0 0
Now all that's left is moving the 12.7 value to where the 1 value is without changing the 0's in the L matrix. and I want to do it with the entire data set. I know I would need another loop, but I don't even know how to go about doing this. and there hasn't been a question on here comparable to my problem. PLEASE HELP.
I HAVE BEEN AT IT FOR LIKE 2 WEEKS!!!!! I'm DYING INSIDE
3 commentaires
Geoff Hayes
le 12 Avr 2019
And I suppose row two would be different? (i.e. 1 is replaced with some other number) Or are all ones replaced with 12.7?
Réponses (2)
Walter Roberson
le 12 Avr 2019
Modifié(e) : Walter Roberson
le 12 Avr 2019
desiredvar = zeros(size(somevariable), class(two));
ind = find(somevariable == 1);
desiredvar(ind) = two(1:length(ind));
In the special case where somevariable is already logical, you could also write
desiredvar = zeros(size(somevariable), class(two));
desiredvar(somevariable) = two(1:nnz(somevariable));
You have not really defined what you want to have happen if somevariable and two are not the same length.
3 commentaires
Walter Roberson
le 15 Avr 2019
nrow = size(O, 1);
ncol = size(O, 2);
output = zeros(nr, ncol);
srccol = 1 * ones(nr, 1);
for C = 1 : ncol
mask = find(L(:,C) == 1);
ind = sub2ind([nrow, ncol], mask, srccol(mask));
output(mask, C) = O(ind);
srccol(mask) = srccol(mask) + 1;
end
I think it would be possible to do without a loop, but I don't think it is worth doing.
Guillaume
le 12 Avr 2019
Modifié(e) : Guillaume
le 12 Avr 2019
" I already have a for loop to set up for the intersect values "
It's very likely that a loop is not needed at all. Show us that code to know for sure.
"Now all that's left is moving the 12.7 value to where the 1 value is without changing the 0's [...] I know I would need another loop"
No, loop absolutely not needed:
O = [12.7 0 0 0];
L = [0 1 0 0]; %double or logical
L(logical(L)) = O(1:nnz(L)); %if L is of class double
L(L) = O(1:nnz(L)); %if L is logical
4 commentaires
Guillaume
le 16 Avr 2019
You wrote (unfortunately, not valid matlab, so we have to interpret):
so if the result is this:
somevariable = 1 0 1 0
two = 6 7 0 0
desiredvar = 6 0 7 0
that's what I want, but I don't know how to get there
>> somevariable = [1 0 1 0];
>> two = [6 7 0 0];
>> desiredvar = somevariable;
>> desiredvar(logical(desiredvar)) = two(1:nnz(desiredvar))
desiredvar =
6 0 7 0
How did that not do what you ask?
Now, if you need the same for each row of a matrix, then give an example, using valid matlab syntax so there's no ambiguity, of the matrices inputs (and corresponding desired output).
The above can always be wrapped in a loop operating on each row of the matrix obviously but most likely it can be done without a loop, e.g.:
tofill = [0 1 0 1;
1 1 0 0];
filler = [10 20 30 40]; %no idea if that's how your input is. Fill by ROW
tofill = tofill'; %matlab works on columns. So transpose
tofill(logical(tofill)) = filler(1:nnz(tofill)); %fill
tofill = tofill' %tranpose back
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