Combine and sorting array values
2 views (last 30 days)
Show older comments
Hello!
I got a result matrix A
A = [3 9 4]
And another matrix B
[ 3 8
4 8
15 5
B= 16 1
16 2
16 7
17 6
17 2 ]
First i want to combine A with all values of the second column of B that have a unique value in the first column -> Matrix AB
AB = [3 9 4 8 5]
As a final result i want the combinations of AB with all values of the second column of B that have not a unique value in the first column ->Result
Result= [3 9 4 8 5 1 6 3 9 4 8 5 1 2
3 9 4 8 5 2 6 3 9 4 8 5 2 2
3 9 4 8 5 7 6 3 9 4 8 5 7 2]
How can i do that?
Many thanks in advance!
0 Comments
Accepted Answer
DGM
on 13 Apr 2022
Edited: DGM
on 13 Apr 2022
Maybe something like:
A = [3 9 4];
B = [3 8
4 8
15 5
16 1
16 2
16 7
17 6
17 2];
U = unique(B(:,1));
c = histcounts(B(:,1),U);
col1unique = ismember(B(:,1),U(c==1));
AB = [A unique(B(col1unique,2),'stable').']
combpool = unique(B(~col1unique,2));
combs = nchoosek(combpool,2);
result = [repmat(AB,[size(combs,1) 1]) combs]
If you want the result formatted as shown, then:
result = reshape(result.',size(result,2)*2,[]).'
6 Comments
DGM
on 16 Apr 2022
Oh I misunderstood what kind of combinations you were after. I was just doing combinations of all remaining (unique) elements of col2.
This does combinations of the groups within col2 associated with the nonunique blocks in col1
A = [3 9 4];
B = [3 8
4 8
15 5
16 1
16 2
16 7
17 6
17 2];
[c ed] = histcounts(B(:,1),'binmethod','integers');
col1unique = ismember(B(:,1),ed(c==1)+0.5);
AB = [A unique(B(col1unique,2),'stable').']
% split col2 of B into groups associated with nonunique elements of col1
Bnonu = B(~col1unique,:);
g = findgroups(Bnonu(:,1));
ngroups = max(g);
elements = cell(1,ngroups);
for k = 1:ngroups
elements{k} = Bnonu(g==k,2);
end
% find combinations of elements between groups
combinations = cell(1,ngroups); %set up the varargout result
[combinations{:}] = ndgrid(elements{:});
combinations = cellfun(@(x) x(:), combinations,'uniform',false);
result = [combinations{:}];
result = [repmat(AB,[size(result,1) 1]) result]
based on this:
More Answers (0)
See Also
Categories
Find more on Shifting and Sorting Matrices 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!