How can I eliminate unwanted zeros from a matrix?
37 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
e.g I want to make this:
1,1,1,1,0,0
1,1,0,0,0,0
1,0,0,0,0,0
1,1,1,1,1,0
into this:
1,1,1,1
1,1
1
1,1,1,1,1
...
Thanks
3 Kommentare
Guillaume
am 16 Jun. 2016
Catherine, please start your own question rather than adding to somebody's else.
Roger Stafford
am 17 Jun. 2016
@Catherine: Let A be your original matrix. You can accomplish what you want with:
T = A~=0;
n = sum(T,2);
m = max(n);
B = nan(size(A,1),m);
for k = 1:size(A,1)
B(k,m-n(k)+1:m) = A(k,T(k,:)); % <-- B is the result
end
Antworten (2)
Justin
am 24 Apr. 2014
Bearbeitet: per isakson
am 17 Jun. 2016
It depends on what you are trying to end up with exactly but a good approach would be to set all zero values to NaN. NaNs wont show up in plots and you can use nanmean() or other functions which ignore NaNs to work with your matrix. This will also retain the shape of your matrix.
arr = [1 1 0; 1 0 1; 0 0 1];
arr =
1 1 0
1 0 1
0 0 1
arr(arr==0) = nan
arr =
1 1 NaN
1 NaN 1
NaN NaN 1
Another option is to use a sparse matrix where the memory only retains information about the index of values.
sparse(arr)
ans =
(1,1) 1
(2,1) 1
(1,2) 1
(2,3) 1
(3,3) 1
You could even convert the array into a cell array and use cellfun to replace all the zeros with an empty array. It would be much more difficult to operate on the information then though.
What are you trying to accomplish with the data?
1 Kommentar
per isakson
am 24 Apr. 2014
Hint:
>> num = [ 1,1,1,1,0,0 ];
>> num( num == 0 ) = []
num =
1 1 1 1
6 Kommentare
Image Analyst
am 24 Apr. 2014
Or the output could be a cell array where you can have different sized rows in each cell. But I don't know why you'd want to mess with that or even want what he's asking for in the first place. Chances are he won't need what he asked for once we learn what he plans on doing with the result.
per isakson
am 24 Apr. 2014
Bearbeitet: per isakson
am 24 Apr. 2014
Agree! I know, I should not try to answer questions like this one.
Siehe auch
Kategorien
Mehr zu Logical finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!