MATLAB: Access a single element of an anonymous function that returns an array

Question

I have an anonymous function that returns an array. I'd like to be able to create a new anonymous function that consists of a single element of this array WITHOUT using matlabfunction (which is infuriatingly restrictive in several respects).

For example, consider the following code (it's a ridiculously simple example, for expository purposes, obviously there are easy ways of dealing with this example, but my real problem is more complex)

y = sym('y',[1,4])
 f = @(y)[y(1);y(2);y(3);y(4)]
 f(y)

which returns

ans =
 y1
 y2
 y3
 y4

I'd now like to define a new anonymous function which extracts, say, the third element of this array. Obviously,

g    = @(y) f(y)(3)

won't work. Is there some way to accomplish this? Again, solns involving matlabfunction are not satisfactory.

Any suggestions would be most appreciated!

Leo

Answer 1

indexat = @(expr, index) expr(index);
g = @(y) indexat(f(y), 3);