# matrix - How do I label two vectors in Matlab?

I have a 2 column matrix(called `M`, which I visualize as two vectors using Matlab's `plot` command(`plot(M)`). I have two issues:

1. I want to label the vectors themselves on the plot.
2. I want to label each row of the matrix(i.e. each vector component) on the plot.

How would I go about doing those things?

An example:

``````M = cumsum(rand(10,2) - 0.5);
x = 1:size(M,1);
plot(x, M(:,1), 'b.-', x, M(:,2), 'g.-')
legend('M1', 'M2')
for i=x
text(i+0.1, M(i,1), sprintf('%.2f', M(i,1)), 'FontSize',7, 'Color','b');
text(i+0.1, M(i,2), sprintf('%.2f', M(i,2)), 'FontSize',7, 'Color','g');
end
``````

Alternatively, you can use:

``````datacursormode()
``````

which will enable the user to just point and click on points to see the data labels.

You may need to tweak this to get the positions of the labels exactly how you want them, but something like this will do the trick.

``````M = [1 2; 3 4; 5 6]
plot(M)
nrows = size(M, 1);
ncols = size(M, 2);
x = repmat(nrows - .3, 1, ncols);
y = M(end, :) - .3;
labels = cellstr([repmat('Col', ncols, 1), num2str((1:ncols)')]);
text(x, y, labels)
``````

You can label each axis with the function:

``````xlabel('label')
ylabel('label')
``````

These can also take cell arguments, where each row is a new line. That's handy for showing units. Labeling each point on the figure can be done as so:

``````for i=1:length(M)
text(M(i,1),M(i,2),'Label Text')
end
``````

The label text can also be a string variable that you can edit with sprintf and make special strings for each point.