Reputation: 41
I have 13 lines on a plot, each line corresponding to a set of data from a text file. I'd like to label each line starting with the first set of data as 1.2, then subsequently 1.25, 1.30, to 1.80, etc., with each increment be 0.05. If I were to type it out manually, it would be
legend('1.20','1.25','1.30', ...., '1.80')
However, in the future, I might have more than 20 lines on the graph. So typing out each one is unrealistic. I tried creating a loop in the legend and it doesn't work.
How can I do this in a practical way?
N_FILES=13 ;
N_FRAMES=2999 ;
a=1.20 ;b=0.05 ;
phi_matrix = zeros(N_FILES,N_FRAMES) ;
for i=1:N_FILES
eta=a + (i-1)*b ;
fname=sprintf('phi_per_timestep_eta=%3.2f.txt', eta) ;
phi_matrix(i,:)=load(fname);
end
figure(1);
x=linspace(1,N_FRAMES,N_FRAMES) ;
plot(x,phi_matrix) ;
Need help here:
legend(a+0*b,a+1*b,a+2*b, ...., a+N_FILES*b)
Upvotes: 4
Views: 19931
Reputation: 74940
As an alternative to constructing the legend, you can also set the DisplayName
property of a line so that the legend is automatically correct.
Thus, you could do the following:
N_FILES = 13;
N_FRAMES = 2999;
a = 1.20; b = 0.05;
% # create colormap (look for distinguishable_colors on the File Exchange)
% # as an alternative to jet
cmap = jet(N_FILES);
x = linspace(1,N_FRAMES,N_FRAMES);
figure(1)
hold on % # make sure new plots aren't overwriting old ones
for i = 1:N_FILES
eta = a + (i-1)*b ;
fname = sprintf('phi_per_timestep_eta=%3.2f.txt', eta);
y = load(fname);
%# plot the line, choosing the right color and setting the displayName
plot(x,y,'Color',cmap(i,:),'DisplayName',sprintf('%3.2f',eta));
end
% # turn on the legend. It automatically has the right names for the curves
legend
Upvotes: 7
Reputation: 161
Use 'DisplayName' as a plot() property, and call your legend as
legend('-DynamicLegend');
My code looks like this:
x = 0:h:xmax; % get an array of x-values
y = someFunction; % function
plot(x,y, 'DisplayName', 'Function plot 1'); % plot with 'DisplayName' property
legend('-DynamicLegend',2); % '-DynamicLegend' legend
source: http://undocumentedmatlab.com/blog/legend-semi-documented-feature/
Upvotes: 6
Reputation: 125874
The simplest approach would probably be to create a column vector of the numbers to use as your labels, convert them to a formatted character array with N_FILES
rows using the function NUM2STR, then pass this as a single argument to LEGEND:
legend(num2str(a+b.*(0:N_FILES-1).','%.2f'));
Upvotes: 1
Reputation: 19216
I found this I found through Google:
legend(string_matrix)
adds a legend containing the rows of the matrixstring_matrix
as labels. This is the same aslegend(string_matrix(1,:),string_matrix(2,:),...)
.
So basically, it looks like you can construct a matrix somehow to do this.
An example:
strmatrix = ['a';'b';'c';'d'];
x = linspace(0,10,11);
ya = x;
yb = x+1;
yc = x+2;
yd = x+3;
figure()
plot(x,ya,x,yb,x,yc,x,yd)
legend(strmatrix)
Upvotes: 0
Reputation: 14958
legend
can also take a cell list of strings as an argument. Try this:
legend_fcn = @(n)sprintf('%0.2f',a+b*n);
legend(cellfun(legend_fcn, num2cell(0:N_FILES) , 'UniformOutput', false));
Upvotes: 5