How can I pass a function name into another function?

I try to make something flexible that gives a function name as a variable name.

Tried the following:

file named tt.m

function tt

x = 0:10;

y1 = testfun(@line,x);

y2 = testfun(@quad,x);

end

file named testfun.m:

function b = testfun(fun, x)

b = fun(x);

function y = line(x)

y = x;

end

function y = quad(x)

y = x.^2;

end

end

How to get it working?

Any help appreciated!

Answer 1

[Stephen23]

The functions that you nested inside TESFUN are only visible within TESTFUN:

https://www.mathworks.com/help/matlab/matlab_prog/nested-functions.html

You could either write them as functions in their own files or write them as normal local functions:

x = 0:10;
y1 = testfun(@line,x)

y1 = 1×11

0 1 2 3 4 5 6 7 8 9 10

y2 = testfun(@quad,x)

y2 = 1×11

0 1 4 9 16 25 36 49 64 81 100

function b = testfun(fun, x)
b = fun(x);
end
function y = line(x)
y = x;
end
function y = quad(x)
y = x.^2;
end

Answer 2

[Torsten]

"fun" is an external input argument to "testfun". Thus "fun" can not be used as a nested function in "testfun".

Using "line" and "quad" as independent external functions that are not nested within "testfun" will work.

Or use

tt

y1 = 1×11

0 1 2 3 4 5 6 7 8 9 10

y2 = 1×11

0 1 4 9 16 25 36 49 64 81 100

function tt
  x = 0:10;
  y1 = testfun(@line,x)
  y2 = testfun(@quad,x)
  function b = testfun(fun, x)
    b = fun(x);
  end
  function y = line(x)
    y = x;
  end
  function y = quad(x)
    y = x.^2;
  end
end