Plot two outputs (or two columns of one output) of a function against each other using only one line of script in an anonymous function

I have the following anonymous functions (this is a much-simplified version for the sake of asking this question) that both produce a new x and y array, which I'd like to plot in a single command (so it can be called within another anonymous function). Function @xy1 outputs two arrays (x and dy), while function @xy2 outputs a single array with x and dy as columns. It doesn't matter which approach is used, they're just the two methods I can come up with and I'm hoping one of them is do-able.

x=[1:10]';
y=rand(10,1);

xy1=@(x,y) deal(diff(y)./diff(x), x(1:end-1)+diff(x)./2);
xy2=@(x,y)[diff(y)./diff(x) x(1:end-1)+diff(x)./2];

[xnew,dy]=xy1(x,y);
xy=xy2(x,y);

I'd like to get the new x and dy arrays to plot as they would if you used plot(xnew,dy), but I need them to plot directly from the function call, something like:

newfunction1=@(x,y) plot(xy1(x,y));

or

newfunction2=@(x,y) plot(xy2(x,y)(:,1),xy2(x,y),(:,2));

Obviously these don't work, but I'm looking for a way to do something similar. Any suggestions would be appreciated. Thanks!

Answer 1

[Walter Roberson]

Given those restrictions, it would be possible to plot using the xy2 function together with a messy subsref() call for the x axes, and then calling xy2 again with a different messy subsref() for the y axes data.

But it would sure be easier and clearer and more efficient if it were permitted to use two lines of anonymous functions, with the function calling the other.

[dandan]

Would you mind providing an example of how you would do this please? It might work for the final function to call a secondary function that relies on more than one anonymous function (I just didn't want to have to use multiple lines of code every time I plot an x-y pair). Thanks!

[Walter Roberson]

plotxy_helper = @(xy) plot(xy(:,1), xy(:,2))
plotxy2 = @(x, y) plotxy_helper(xy2(x, y));

This invokes xy2 once and receives the result back as a nameless array, which is then passed to plotxy_helper which pulls it apart to use the parts.

[dandan]

This works, thanks so much for the clarification!