Given the element in a matrix, how to get the corresponding element in cell array?(cell2mat, mat2cell)

There is a cell array, saying A = {a_1 x b, a_2 x b, a_3 x b, ..., a_n x b}.

After doing B = cell2mat(A), I can get a matrix B, which is (a_1+a_2+...+a_n) x b.

After processing the matrix B, I get my wanted elements in B, saying they are x, which is the row index of Matrix B.

How can I get the corresponding element in original cell A?

For example, if x = 1, it must come from the first element in A. If x > a_1 && x < a_2, it must come from the second element in A.

Is there any function in matlab?

Thanks,

Zhong

Answer 1

[Andrei Bobrov]

eg

A = arrayfun(@(x)randi(12,randi(6),6),1:7,'un',0)
B = cat(1,A{:})
I=17;J=1;
B(I,J)

%solution
idx = cumsum([0 cellfun('size',A,1)])
nocell = find(idx < I,1,'last')
Ic = I - idx(nocell)
A{nocell}(Ic,J)