I have something like this:
p = plot([0 1], [0 1], [1 2], [1 2]);
I want to take each pair and append another number.
x = get(p, 'XData');
y = get(p, 'YData');
x1 = mat2cell([x{1} double(2)]);
y1 = mat2cell([y{1} double(2)]);
x2 = mat2cell([x{2} double(3)]);
y2 = mat2cell([y{2} double(3)]);
set(p, 'XData', [x1; x2], 'YData', [y1; y2]); % this does not work
drawnow;
'get' is giving me some data in a format and I am 'set'-ing back in the same format the data with one more value for each pair.
The error I get is: Conversion to double from cell is not possible.
There are a number of different ways to fetch the current plot points and add to them. The first two lines of Eitan's answer (using cellfun) are one way. Here's one using cell2mat and num2cell:
newX = [2 3]; % New x values to add
newY = [2 3]; % New y values to add
X = num2cell([cell2mat(get(p,'XData')) newX(:)], 2);
Y = num2cell([cell2mat(get(p,'YData')) newY(:)], 2);
The key issue to note when using the set function on multiple handles is stated in this excerpt from the documentation:
set(H,pn,MxN_pv) sets n property values on each of m graphics objects, where m = length(H) and n is equal to the number of property names contained in the cell array pn. This allows you to set a given group of properties to different values on each object.
As a result, your single call to set has to look like this:
set(p, {'XData'}, X, {'YData'}, Y);
Note that length(p) is equal to 2, the property strings are placed in cell arrays, and X and Y are each 2-by-1 cell arrays.