How to change color of lines on legend?

Is there any way to change the color of lines in the legend AFTER plotting the graph(like using Edit\axes properties)?

[Walter Roberson]

But not changing the colors of the original lines? Just of the legend entries? That sounds confusing to the user.

[Mahdi Torabi]

I want to change the color of line on the legend, not plotted data. The graph has two legends and plotted from a big loop. At the end there are same colors (both blue) for both lines which represented in the legend box however the data itself are in blue and red. This is because the graph is in big loop. Now I want to change the color of second line of legend to red without changing anything in data.

[Walter Roberson]

You could record the handle of the first of each type, and then pass that vector of handles as the first argument to legend().

Or you could do something like

L(1) = plot(nan, nan, 'b-');
L(2) = plot(nan, nan, 'r--');
legend(L, {'first case', 'second case'})

[Mahdi Torabi]

Thank you so much. This solved the problem.

Answer 1

[Mahdi Torabi]

According to the Walter answer on above my problem solved easily using :

L(1) = plot(nan, nan, 'b-');

L(2) = plot(nan, nan, 'r--');

legend(L, {'first case', 'second case'})

[Matt J]

This gives an error,

Error using legend>process_inputs (line 554)
Invalid argument. Type 'help legend' for more information.

Error in legend>make_legend (line 306)
[autoupdate,orient,location,position,children,listen,strings,propargs] = process_inputs(ha,argin); %#ok

Error in legend (line 259)
    make_legend(ha,args(arg:end),version);

[Walter Roberson]

Turns out you just need

hold on

to be in effect, as otherwise the second plot() clears the axes.

Answer 2

[Matt J]

This might be what Walter meant,

t=linspace(0,1,10);

L(1:2) = plot(t,exp(-t), 'r--',nan,nan,'k--');hold on
L(3:4) = plot(t,1-exp(-t), 'g^-',nan,nan,'m^-'); hold off

legend(L([2,4]), 'Red','Green')

[Luiz Bacelar]

how to solve this? I have similar problem

[Walter Roberson]

plot(nan,nan) with appropriate line style and color, once for each different thing you want to appear in the legend, recording the handle that is returned. Then when you call legend(), pass that array of handles in as the first parameter to legend()