Need to get dimensions to match and to return a 0 x 0 matrix for empty row.

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This code give me a 1 x 0 array for any row that is empty. I need it to return a 0 x 0 empty matrix for any row that is empty. It is presently giving me an error and proclaiming that the dimensions of the object in the "if" statement don't match.
function S = logipack( V)
m = size(V, 1);
S = cell(m, 1);
for r = 1:m
S{r} = find(V(r, :));
if find(V(r,:))==[]
S{r}= [];
end
end
end
  5 Comments
DJ V
DJ V on 17 Dec 2016
Edited: DJ V on 17 Dec 2016
V is a matrix of 1's and 0's. IF there is a 1 in a row the logipack software is supposed to identify the column numbers where it occurs. If there are no 1's, the software is supposed to return an empty vector of size 0 x 0.
Jan
Jan on 18 Dec 2016
@DJ V: You discus the problem "find(V(r,:))==[]" here, although the answer I've given at https://www.mathworks.com/matlabcentral/answers/317178-what-is-wrong-with-this#answer_247497 contains the correct isempty() already. By this way, you do not catch attraction, but discourage readers to care about your questions.

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Accepted Answer

John BG
John BG on 16 Dec 2016
DJ
MATLAB moans, not because of if condition mismatch, but because the operator '==' doesn't work for cells, try this:
cell1 =
'a' [1] '9' [2x2 double]
>> cell2={'b' 2}
cell2 =
'b' [2]
>> cell1==cell2
Undefined operator '==' for input arguments of type 'cell'.
So,
1.- your 1st line in the for loop doesn't make much sense,
S{r} = find(V(r, :))
so I changed it to
S{r} = V(r, :)
may be it's not what you want but at least now S is not empty.
2.- instead of
if find(V(r,:))=={}
try
if isempty(V(r,:))
or better
if isempty(V(r))
So the following, although not sure whether of much use, at least it doesn't crash
V=randi([-10 10],1,10)
m = size(V, 2);
S = cell(m, 1);
for r = 1:m
S{r} = V(r);
if isempty(V(r))
S{r}= [];
end
end
if you find this answer useful would you please be so kind to mark my answer as Accepted Answer?
To any other reader, please if you find this answer of any help solving your question,
please click on the thumbs-up vote link,
thanks in advance
John BG
  3 Comments
DJ V
DJ V on 17 Dec 2016
Just in case anyone is curious, this code works and passes the grader:
function out = logipack(V)
m = size(V, 1);
S = cell(m, 1);
for r = 1:m
S{r} = find(V(r, :));
end
for r = 1:m
for q = 1:m
if q==1
count=0;
end
if V(r,q)==0
count= count+1;
end
if count==m
S{r,1}=[];
end
end
end
out = S;
end

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More Answers (1)

the cyclist
the cyclist on 16 Dec 2016
You can probably take advantage of the isempty command here.

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