How to make one matrix?

Hi

I have 100 arrays i.e. each have one row and diffrent columns (say size is A = 1 * 167 and B = 1 * 189 and so on). I want to make one matrix in way that the first row is A, second row is B and so on... But the columns will remain different. How can I do it?

[Benjamin Thompson]

Like this?

>> A = [1 2 3 4]

A =

1 2 3 4

>> B = [5 6 7 8]

B =

5 6 7 8

>> C = [A; B]

C =

1 2 3 4

5 6 7 8

If this is not right please explain more what output you want. Perhaps with a smaller example of 4 arrays what will the output look like?

[Torsten]

No, like this:

A = [1 2 3 4]

A = 1×4

1 2 3 4

B = [5 6 7 ]

B = 1×3

5 6 7

C = [A; B]

Error using vertcat
Dimensions of arrays being concatenated are not consistent.

[Ahmed]

@Torsten No this is not working e.g.,

ITER = [iters_1; iters_2];

Error using vertcat

Dimensions of arrays being concatenated are not consistent.

Error in PLOTTING_UNCERTINITY (line 172)

ITER = [iters_1; iters_2];

[Stephen23]

"How can I do it?"

https://www.mathworks.com/matlabcentral/fileexchange/22909-padcat

https://www.mathworks.com/matlabcentral/answers/1656435-tutorial-comma-separated-lists-and-how-to-use-them

Answer 1

[Torsten]

Either use a cell array or dimension the matrix to have the maximum number of columns of the 100 row vectors:

A = [1 23 45];
B = [1 2];
M1 = cell(2,1);
M1{1} = A;
M1{2} = B;
M1

M1 = 2×1 cell array
    {[1 23 45]}
    {[    1 2]}

n = max(size(A,2),size(B,2));
M2 = zeros(2,n);
M2(1,:) = [A,zeros(1,n-size(A,2))];
M2(2,:) = [B,zeros(1,n-size(B,2))];
M2

M2 = 2×3

1 23 45 1 2 0

[Ahmed]

Hi, @Torsten

Thanks, it is working but if I have 500 rows then it will be too long to code this way. Is there any short way?

[Walter Roberson]

I have 100 arrays

What form do you have the 100 arrays in?

If you have them stored in seperate variables... then you have a problem. Don't store them in seperate variables.

http://matlab.wikia.com/wiki/FAQ#How_can_I_create_variables_A1.2C_A2.2C....2CA10_in_a_loop.3F

[Ahmed]

Hi,

Thanks for your reply. actually all the variables are stored separetly. If I do as @Torsten sugested (e.g., given below), zero appears to make size equal. How to get rid off these zeros during plotting? You can see these are appearing in figure as well (circled part).

hist_1 = hist_1./max(hist_1);

hist_2 = hist_2./max(hist_2);

M1 = cell(2,1);

M1{1} = hist_1;

M1{2} = hist_2;

n = max(size(hist_1,2),size(hist_2,2));

M2 = zeros(2,n);

M2(1,:) = [hist_1,zeros(1,n-size(hist_1,2))];

M2(2,:) = [hist_2,zeros(1,n-size(hist_2,2))];

figure, plot(iters_2,M2)

[Stephen23]

"How to get rid off these zeros during plotting?"

Replace ZEROS with NAN. Or use the approach I gave you here:

https://www.mathworks.com/matlabcentral/answers/2075401-how-to-make-one-matrix#comment_3045381

"actually all the variables are stored separetly."

Having lots of separate variables makes your data much harder to work with.

It is much better to use a cell array or structure array.

[Walter Roberson]

Whatever process is loading all that data into seperate variables: it would be better if it loaded it all into a cell or a struct array to start with.