grouping data in column vector based on another vector

Hello

I have a column vector A as [0;1;2;3;4]. On the other hand, there is another column vector called C=[15;16 ;17; 18; 20;19;7;8;22;25].

I want to group data in matrix C based on arrays in A such that A(1)=0 then nothing is selected from C so C(1)=0. Then as A(2)=1, so the first array from C is selected so C(2)=15. Then as A(3)=2 so two arrays from C are selected so 16 and 17 are grouped together as C(3)=[16,17]. Then as A(4)=3, so C(4)=[18,20,19]. And finally, A(5)=4 so C(5)=7,8,22,25].

Any idea is highly appreciated.

Bests

Answer 1

[KSSV]

A = [0; 1; 2; 3; 4] ;
B = [15;16 ;17; 18; 20;19;7;8;22;25] ; 
N = length(A) ; 
C = cell(N,1) ;
for i = 1:N
    if A(i) == 0 
        C{i} = 0 ;         
    else
        C{i} = B(1:A(i)) ;
        B(1:A(i)) = [] ;
    end
end
celldisp(C)

 
C{1} =
 
     0

 
 
C{2} =
 
    15

 
 
C{3} =
 
    16
    17

 
 
C{4} =
 
    18
    20
    19

 
 
C{5} =
 
     7
     8
    22
    25

 

[Pooneh Shah Malekpoor]

Thanks!

Answer 2

[Dyuman Joshi]

Assuming that sum(A) == numel(C), You can use for loops and cell arrays to get the result

X=C; %Assigning C to another variable in case you need C again 

for i=1:numel(A)
    if A(i)==0
        Y{i}=0;
    else 
        Y{i} = X(1:A(i))';
    end
    X(1:A(i))=[];
end

Y = 1×5 cell array
    {[0]}    {[15]}    {[16 17]}    {[18 20 19]}    {[7 8 22 25]}

P.S - This might not be the most efficient method. There was a similar Cody question, if I find a better solution, I will update it here.