legend for group of lines

Question

I like to plot two groups of lines in the same plot. Each group has two lines with same color and I have to draw them in the order of one group after another group. I try to

Answer 1

In response to your update, and to extend Andrew Janke's answer, I found this method to be perfect for an automatic legend:

% Sample data
order = -1:2;      % number of orders to plot
x = (0:0.01:10)';

% Plot each instance of data in a separate graph
for i=1:numel(order)
    plot(x,besselj(order(i),x))
    hold all

    % Amend legend to include new plot
    [~,~,~,current_entries] = legend;
    legend([current_entries {sprintf('Order = %i',order(i))}]);
end

Gives the following figure:

EDIT: In Matlab 2014b, the use of "legend" has changed and the solution(s) above will throw errors. Instead, we should modify the 'String' property of the legend. Follow this code to get the same result as my previous example:

% Sample data
order = -1:2;      % number of orders to plot
x = (0:0.01:10)';

% Plot each instance of data in a separate graph
for i=1:numel(order)
    plot(x,besselj(order(i),x))
    hold on

    % Amend legend 'entries' to include new plot
    entries(i) = { sprintf('Order = %i',order(i)) };
end

% Create legend using the 'entries' strings
legend('String',entries);

Now you can add as many plots as you want and the legend will automatically update!