detect same value
9 views (last 30 days)
Show older comments
how do I detect on the elements of a (:, 1) there is the same value?
a=[1 34;
2 33;
2 45;
3 32;
4 65;
4 99;
5 11;
1 33;
6 22]
0 Comments
Accepted Answer
Walter Roberson
on 10 Jun 2011
u = unique(a(:,1));
if length(u) ~= size(a,1)
%there were duplicates
end
If you want to find out which are equal to which,
bsxfun(@eq, a(:,1), a(:,1).'))
and that will return a logical matrix in which for row r, column c is set if a(r) == a(c)
2 Comments
M M
on 6 Mar 2013
How would you isolate the duplicated values? So I would know which values are duplicated and use them for another purpose? (The opposite of the unique function)
Walter Roberson
on 6 Mar 2013
setdiff(V, unique(V)) %for vector V, results are in sorted order
or
T = bsxfun(@eq, V(:), V(:).'); %for vector V
sum(T) > 1 %will be true at index K if V(K) is not unique
More Answers (0)
See Also
Categories
Find more on Logical in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!