Help for matrix in matlab

How to convert a 20*20 matrix into 20*1 matrix in matlab

[Riccardo Scorretti]

Hi Amy, the problem as formulated is ill posed. What do you mean exactly by "converting a matrix"? Please, provide a simple example of what you want to do.

Answer 1

[Kautuk Raj]

I am assuming that you wish to get a 400x1 matrix, instead of a 20x1 matrix, the latter being not possible without dropping elements. To convert a 20x20 matrix into a 400x1 matrix in MATLAB, we can use the reshape function. To cite an example:

% Define a 20x20 matrix
A = rand(20);
% Reshape the matrix into a 400x1 column vector
A_col = reshape(A, [], 1);

In this code, we first define a 20x20 matrix A using the rand function to generate random values. We then use the reshape function to reshape the matrix into a 400x1 column vector A_col.

More details about the reshape function can be found here.

[the cyclist]

The result is not a 20x1 column vector:

% Define a 20x20 matrix
A = rand(20);
% Reshape the matrix into a 20x1 column vector
A_col = reshape(A, [], 1);

size(A_col)

ans = 1×2

400 1

What the OP asked for is not possible without further information about what they mean.

Answer 2

[Walter Roberson]

prod(M, 2)
sum(M, 2)
min(M, 2)
max(M, 2)
any(M, 2)
all(M, 2)
std(M, [], 2)

amongst others

[the cyclist]

How silly can we get, within the bounds of the request?

M(randperm(400,20))'; %  :-)