Get data vector from stairstep plot Matlab

Question

How can one get the data vectors from the output of the stairs function in Matlab? I tried the following

h = stairs(x,y);

Then I get the data from the handle:

x = h.XData; 
y = h.YData; 

but when x and y are plotted, they look as a piece-wise function, not the stairs.

Any help is appreciated. Thanks!

Answer 1

The data necessary to display a stairs plot are relatively easy to generate by yourself.

Assuming you have x and y. To generate 2 vectors xs and ys such as plot(xs,ys) will display the same thing than stairs(x,y), you can use the following 2 steps method:

• replicate each element of x and y
• offset the new vectors by one element (remove the first point of one vector and the last point of the other)

Example with code:

%% demo data
x = (0:20).';
y = [(0:10),(9:-1:0)].' ;

hs = stairs(x,y) ;
hold on

%% generate `xs` and `ys`
% replicate each element of `x` and `y` vector
xs = reshape([x(:) x(:)].',[],1) ;
ys = reshape([y(:) y(:)].',[],1) ;

% offset the 2 vectors by one element
%  => remove first `xs` and last `ys`
xs(1)   = [] ;
ys(end) = [] ;

% you're good to go, this will plot the same thing than stairs(x,y)
hp = plot(xs,ys) ;

% and they will also work with the `fill` function
hf = fill(xs,ys,'g') ;