Handles for individual matrix columns/rows/elements -- Matlab

Question

I'm currently using Matlab and I am plotting the contents of the rows of a matrix, where each column is an independent data set. As the matrix is large I don't want to have to go through the tedius task of writing up the plot labels for each data set individually, so I was wondering if there is a specific way to include a handle/name for each column in such a way that it will automatically apply the plot label, and will adjust accordingly if columns are added or removed from the matrix?

Thanks!

Specifics, if they help: Amplified spontaneous emission (ASE) in an optical fibre amplifier. Rows act as storage for a discretised ASE spectrum, columns are a given position along the fibre amplifier (it is this position -- the distance along the fibre corresponding to the column -- which I want to use as the label) and each element contains power information. The plot gives spectral power of ASE in the fibre for different positions along its length.

angainor angainor · Accepted Answer · 2012-09-18T15:58:25

If by labels you mean the plot legend, you can do that by using cells. Consider matrix A

A = repmat([1:3], 3, 1)

A =

 1     2     3
 1     2     3
 1     2     3

You can call plot to plot the columns of the matrix

plot(A);

Here, you will get 3 horizontal lines at y=1, 2 and 3. You can create your legend as follows

l{1} = 'dataset1';
l{2} = 'dataset2';
l{3} = 'dataset3';

Then you type

legend(l)

to show the legend. However, no one will create the legend for you, so you must create the cell array yourself. You can do it automatically, of course, e.g. the above legend can be created by a simple loop

for i=1:size(A, 2)
   l{i} = ['dataset' num2str(i)];
end

Handles for individual matrix columns/rows/elements -- Matlab

1 Answers