Legend Title Indexing - Keeps Overwriting

Hey!

So I have a plot that has multiple data sets overlaid and I am trying to get the legend to portray the data name for each data set. The tricky part comes from the name of the file, which is imported from a file in a folder path. This is stored as a string variable called "string". The problem I am having is that everytime the for loop runs the legend data name is replaced by the new file name and only displays that line in the legend. I am looking for a method of allowing the legend to index the name of the data set so that it matches what is on the graph and keep them all displayed with the data sets to find errors. The picture attached show my plotting code(circled in red) and the output. Currently there are only 3 files but the eventual goal is to have it scripted so that it can tackle hundreds of files of different types which is why I want to use the file name I pull from the folder without manual input. Is this possible, or is there anyway to format the data to make it possible?

Answer 1

[Les Beckham]

One approach that should work is to wait to generate the legend until after the loop is done.

Replace the two lines

stringTmp = strrep(string, '_', '-');
legend(stringTmp)

with this:

legendStrings = {legendStrings; strrrep(string, '_', '-')};

Add this above your for loop to initialize legendStrings as an empty cell array:

legendStrings = {};

Then add this after the end of the for loop:

legend(legendStrings)

Answer 2

[Steven Lord]

Another way to do this is to let each line know what should be added to the legend when you create the line.

When you call plot set the DisplayName property of the line. When you want to display or update the legend, call legend show.

x = 0:360;
axis([0 360 -1 1]);
hold on
for k = 1:4
    plot(x, sind(k*x), 'DisplayName', "sin(" + k + "*x)");
end
legend show