MATLAB: Adding random data to left and right of each element in a matrix

matrix

This is a change from my previous question with random elements instead of fixed elements
https://www.mathworks.com/matlabcentral/answers/365828-adding-data-to-two-matrices-for-indexing#answer_290019
Take for example,
i have two 3×4 matrices, M=
1       2        3          4
5       6        7          8
9      10        11        12
and E which shows the number of elements to be added to matrix M, random from 1-4
    4       2        1          2
    2       3        4          1
    1       3        2          3
The elements to be added are random numbers from 0.1 to 0.9, the result to be obtained is shown below
1.3   1.9   1.4   1.1   1  1.5   1.3   1.9   1.7        2.2    2.4   2   2.9   2.5      3.1  3  3.7     4.8   4.2   4   4.4   4.1
5.3   5.8   5   5.5   5.1        6.6   6.1   6.3   6   6.2   6.2   6.7       7.2   7.3   7.2   7.9   7   7.1   7.5   7.4        8.8   8   8.2 
9.2   9   9.5   10.9   10.7   10.6   10   10.4   10.3   10.4   11.3   11.4   11   11.1   11.9       12.3   12.9   12.5   12   12.3   12.4   12.8
Next is how do i store this data since it no longer stays as a matrix and is it possible use indexing to find a certain value eg. find(M==2)

Best Answer

M = [
  1       2        3          4
  5       6        7          8
  9      10        11        12];
E = [
    4       2        1          2
    2       3        4          1
    1       3        2          3];
%
foo = @(m,e) m+randi(9,1,e)/10;
fun = @(m,e) [foo(m,e),m,foo(m,e)];
C = arrayfun(fun,M,E,'Uni',0);
Giving the output in a cell array C, where each cell contains a vector based on one element of M, e.g. the first column of C:
>> C{:,1}
ans =
   1.4000   1.3000   1.9000   1.3000   1.0000   1.9000   1.1000   1.3000   1.9000
ans =
   5.6000   5.6000   5.0000   5.9000   5.5000
ans =
   9.1000   9.0000   9.3000
>>
" how do i store this data since it no longer stays as a matrix..."
I showed you how to put this into a cell array which is the same size as your original matrices. Alternatively you could extract all of the numeric data and concatenate it into one long numeric vector.
"...and is it possible use indexing to find a certain value eg. find(M==2)"
That depends on how your decide to store it: storing in a cell array requires a different way of searching than if you use one numeric vector.
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