read the matrix elements of the loop and value them separately

A text file has a matrix with 2 columns and too many rows. The first element of this matrix in each line x, the second element y I want to say. How can I do this as a loop? I'll use these x and y in a calculation. Thanks in advance.

[pragnan nadimatla]

As per my understanding, you have a matrix of 2 columns and multiple rows, and you want to store 1st element of every row and 2nd element of every row separately to use these for further computation.

You can do this by referring the below code. Here, I have created a random matrix of 10 rows and 2 columns and initialised 2 vectors “x” and “y” with zeros. I have iterated through all rows and 1st element and 2nd element have been extracted using matrix(i,1) and matrix(i,2).

% Create a random matrix of 10 rows and 2 columns
A = rand(10, 2);
% Initialize x and y vectors with zeros
x = zeros(10, 1);
y = zeros(10, 1);
% Loop over all rows of the matrix
for i = 1:size(A, 1)
    % Read the first element of the i-th row into x
    x(i) = A(i, 1);
    
    % Read the second element of the i-th row into y
    y(i) = A(i, 2);
end

[Aakash]

Please give a sample of how data looks in the text file

[Dyuman Joshi]

It's not clear what exactly you want to do.

Do you want the data in 2 column assigned to 2 different variables? Then simply do this

%Let M be the array
x = M(:,1);
y = M(:,2);

There is no need of for loop for this.

If you want to do something else, then please specify your query (best with an example).

Answer 1

[Sarthak]

Hello Busra,

What I understand from your question is that you have a matrix of dimensions n*2 and you want to set the value of second element of every row to something. For this, you can write a function as mentioned below, and save it to some location with the same name as the function name, go to that loaction and run the function in the terminal.

Note : The code attached sets the second element of every row equal to the row index, you can modify it according to your requirement.

% The function sets the second column of a matrix equal to the index of the
% row

function outputMatrix = setSecondColumn(inputMatrix)
    % Get the number of rows in the matrix
    [rows,~] = size(inputMatrix);
    % Loop through rows and set the second element of each row
    for i=1:rows
        inputMatrix(i,2) = i;
    end
    % Return the output matrix
    outputMatrix = inputMatrix;
end