Obtain lists of plot marker and line styles in Octave

Question

Is there a way to programmatically obtain the list of marker and line styles available for plotting in Octave?

Ideally, I would do something like

mslist = whatever_function_for_marker_styles;
lslist = whatever_function_for_line_styles;
for i = 1:np
    plot(x, y(i,:), 'marker', mslist(i), 'linestyle', lslist(i))
endfor

Notes:

1. I would add some mod functions to cycle across the lists.
2. I know the size of both lists may not be the same, so they may shift from one another upon cycling.

Answer 1

I agree with Howard that doing it 'entirely' programmatically is probably overkill.

However, if you do want to do that, my bet would be to parse the 'help' output for the 'plot' command, which is guaranteed to mention these points, and has a reasonable guarantee that it will remain in the same format even if more markers are added in the future etc.

I won't parse the whole thing, but if you were to do this, you'd probably start like this:

plotdoc = help('plot');                                                                                                                                                                                                                                                                                                       
[plotdoc_head   , plotdoc_rest] = deal( strsplit( plotdoc     , '     linestyle' ){:} );                                                                                                                                                                                                                                      
[plotdoc_lines  , plotdoc_rest] = deal( strsplit( plotdoc_rest, '     marker'    ){:} );                                                                                                                                                                                                                                      
[plotdoc_markers, plotdoc_rest] = deal( strsplit( plotdoc_rest, '     color'     ){:} );                                                                                                                                                                                                                                      
[plotdoc_colors , plotdoc_rest] = deal( strsplit( plotdoc_rest, '";displayname;"' ){:} );                                                                                                                                                                                                                                     

or something along those lines, and then use regexp or strfind / strtoken / strplit creatively to obtain the necessary tokens in each category.

Answer 2

The easiest way would be to get the symbols from the manual and put them in a cell array:

mslist = {'+', 'o', '*', '.', 'x', 's', 'd', '^', 'v', '>', '<', 'p', 'h'};

lslist = {'-', '--', ':', '-.'};

You can loop over them with a standard for-loop and access them by index using curly brackets, e.g. lslist{i}. The symbols are in Section 15.2.1 of the manual (https://octave.org/doc/v6.1.0/Two_002dDimensional-Plots.html#Two_002dDimensional-Plots). An ordinary vector would work for mslist instead of a cell array as all the symbols are single characters, but not for lslist where some of them are two characters long.