CODEWITHSUNDEEP
matlabmatrix
Raldenors
Raldenors

Reputation: 311

How to combine numbers and add up numbers in different column

This is continuation of my previous questions (one, two) and this is my real problem I have an array of data:

a   b   c   d
0   1   2   5
0   1   7   1
0   0   5   5
0   0   0   1
0   1   0   2

as you can see i want abc to be combine and in one column, just like this:

abc    d
012    5
017    1
005    5
000    1
010    2

so i will now have 2 columns abc and d

next i want to count repeated values of d, add it up and combined those corresponding abc, see below

abc        d
012,005    10
017,010    2
010        5

so as you can see, 012, and 005 combine because they have the same value of d, and their d add up so it become 10, so how i can do that? this is my real problem please help thanks.

Upvotes: 1

Views: 89

Answers (1)

Robert Seifert
Robert Seifert

Reputation: 25232

A = [...
0   1   2   5;
0   1   7   1;
0   0   5   5;
0   0   0   1;
0   1   0   2 ]

%// column for identification
subs = A(:,4);
%// get order for sorting output
order = unique(subs,'stable')

%// get strings from numbers
abc = cellstr(reshape(sprintf('%i',A(:,1:3)),size(A(:,1:3))))

%// gather abc
groups = accumarray(subs,1:numel(subs),[],@(x) {abc(x)})

%// sum counts
counts = accumarray(subs,subs,[],@sum)

%// output
out = [groups num2cell(counts)]

%// reorder output
out = out(order,:)

%// filter output
out(find(~counts(order)),:) = []

out = 

    {2x1 cell}    [10]
    {2x1 cell}    [ 2]
    {1x1 cell}    [ 2]

with for example

out{1,1} = 

'005'
'012'

As you see out{1,1} is still not in the correct order. The reason is that accumarray is not stable. To solve it, use the function accumarrayStable provided in the link:

function A = accumarrayStable(subs, val, varargin)
[subs(:,end:-1:1), I] = sortrows(subs(:,end:-1:1));
A = accumarray(subs, val(I), varargin{:});
end

and you will finally get:

out{1,1} =

    '012'
    '005'

Upvotes: 4

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