store in a column vector x the first column of the file input.txt in matlab

You can use the importdata function to read the data from the file into the matrix variable A. Then, you can index into the first column of A using : and store the result in the column vector x using the transpose function or the apostrophe symbol. Here's an example code snippet that demonstrates this approach:

main.m
A = importdata('input.txt');
x = A(:,1)';
42 chars
3 lines

Alternatively, you can use the dlmread function to directly read the first column of the file into the column vector x. Here's an example code snippet that demonstrates this approach:

main.m
x = dlmread('input.txt', '\t', [0 0 size(A,1)-1 0]);
53 chars
2 lines