Question

I have a matrix 2×20 from a text file
I want to add a row of ones to that matrix

twopts = reshape(textread('input.txt', '%s'),2,20); % 2 by 20
ones_row = ones(1,20);   %1 by 20 of ones

twopts = [twopts;ones_row]

Gives me an error:

“Error using vertcat CAT arguments dimensions are not consistent.”

But the matrix dimensions match… 2×20 and 1×20 to make 3×20

What’s wrong with it and how do I fix it?

Answer 1

twopts is a cell array of strings and ones_row is a matrix, you can’t put these together.

Does this do what you want?

twopts = reshape(textread('input.txt', '%s'),2,20); % 2 by 20
ones_row = ones(1,20);   %1 by 20 of ones
ones_row = mat2cell(ones_row, 1, ones_row); % convert to cell array

twopts = [twopts;ones_row]

Alternatively, if the input data contains numbers, not text, you might want to convert the cell array to a matrix instead:

twopts = reshape(textread('input.txt', '%s'),2,20); % 2 by 20
twopts = cellfun(@str2num,twopts);
ones_row = ones(1,20);   %1 by 20 of ones

twopts = [twopts;ones_row]