Store values in cells based on their potition.

I have a matrix A=[1,2,3,6,7,8,11,12,13,14,15,17,18,19,30,31,32 ; 30,38,42,56,64,82,96,67,88,46,37,94,65,82,97,106,89]] A=(2x17)

The values of the firtst row are stored, baced on vector jumps, in cell array like :

C = {[1 2 3]} {[6 7 8]} {[11 12 13 14 15]} {[17 18 19]} {[30 31 32]}

how can i find the potition that each one of these values have correspondence with the first matrix in order to also store the values of the second row in commensurable potitions?

The output i want is :

V = {[30,38,42]} {[56,64,82]} {[96,67,88,46,37]} {[94,65,82]} {[97,106,89]}

P.S what's the difference if the first row of the matrix A is made up of ''date time'' values? (I thinks i can not use the command ''find'').

Answer 1

[Voss]

Calculate V at the same time as C, using the same indices dervied from the first row of A, but applied to the second row:

(Using this answer for reference.)

A = [ ...
     1, 2, 3, 6, 7, 8,11,12,13,14,15,17,18,19,30, 31,32; ...
    30,38,42,56,64,82,96,67,88,46,37,94,65,82,97,106,89];
C = {};
V = {};
ind = [1 find(diff(A(1,:)) ~= 1)+1 size(A,2)+1];
for n = 1:numel(ind)-1
    C{n} = A(1,ind(n):ind(n+1)-1);
    V{n} = A(2,ind(n):ind(n+1)-1);
end
C

C = 1×5 cell array
    {[1 2 3]}    {[6 7 8]}    {[11 12 13 14 15]}    {[17 18 19]}    {[30 31 32]}

V

V = 1×5 cell array
    {[30 38 42]}    {[56 64 82]}    {[96 67 88 46 37]}    {[94 65 82]}    {[97 106 89]}

P.S for a datetime array, I guess you will have to define what "consecutive" means. I mean, in this case using positive integers, "consecutive" is naturally defined as differing by 1, but for datetime arrays, should elements differing by 1 day be considered "consecutive"? Those differing by 1 second? 1 month? How about 6 weeks, why not?

[PANAGIOTIS GEORGIOS ILIOPOUOS]

Very insightfull!!

thanks for answering

[AndresVar]

@PANAGIOTIS GEORGIOS ILIOPOUOS here is alternative using ismember: Array elements that are members of set array - MATLAB ismember (mathworks.com)

A=[1,2,3,6,7,8,11,12,13,14,15,17,18,19,30,31,32 ; 
    30,38,42,56,64,82,96,67,88,46,37,94,65,82,97,106,89];

C = {[1 2 3],[6 7 8],[11 12 13 14 15],[17 18 19],[30 31 32]}

C = 1×5 cell array
    {[1 2 3]}    {[6 7 8]}    {[11 12 13 14 15]}    {[17 18 19]}    {[30 31 32]}

Asplit = C; % pre allocates
for ii = 1:numel(C)
    Asplit{ii}=A(2,ismember(A(1,:),C{ii}));
end
Asplit

Asplit = 1×5 cell array
    {[30 38 42]}    {[56 64 82]}    {[96 67 88 46 37]}    {[94 65 82]}    {[97 106 89]}

can also try using the second output from intersect: Set intersection of two arrays - MATLAB intersect (mathworks.com)

also if C is always going to be a running string maybe you can use bin edges instead and use discretize.

[PANAGIOTIS GEORGIOS ILIOPOUOS]

Very helpfull thank you!!!!