How to read a matrix from a text in Matlab

Question

I recently ran into this the other day, I'm not that good of a programmer, and the teacher asked us to make a program that reads a square matrix from a txt. and then use the information to solve it. I've been wondering how to do the first part of this program as I already figured it out how to solve the matrix, but I just don't know how to do the scanning of the text. Just so you guys can understand me, this is how the text would look like:

4

1 2 3 8

7 4 1 2

1 2 1 2

3 4 5 6

So as you can see, it has to read the first number and store it in a variable so the program knows the size of the matrix and then read the matrix and store it in an array or so I think.

Any help would be apreciated.

Answer 1

D = importdata('file.txt');
rows = D(1);
cols = (numel(D)-1)/rows;
D = reshape(D(2:end),[cols rows])';

(best MATLAB solution would be to remove the number of rows in the beginning. Then importdata would be sufficient)

Answer 2

suppose file.txt is

1 2 3 8

7 4 1 2

1 2 1 2

3 4 5 6

The command is

load file.txt

and then you get a variable file

the size of file is [4,4] .