how to use an array as the input variable for function

I would like to use an array as the input to call the main function. how to make it?

E.g

function [a b c]=myfunc( x1,x2,x3,x4, ...xn)

a=x1+x2;

b=a;

c=x1*x2*x3...xn;

end

Now I want to use below array as the input to call above function.

Input_data=[¨1 2 3 4 ....n]

feval(myfunc, [1 2 3 4 ... n]) then it's working. But I want to use an array Input to make it rather than list these values.

feval(myfunc, Input_data ) is not working becasue all the values assign to the first variable x1

help help

Answer 1

[Chunru]

% Now I want to use below array as the input to call above function.
Input_data=[1 2 3 4  5];
%feval(myfunc, [1  2 3 4 ... n])  
[a, b, c] =myfunc(Input_data)

a = 3

b = 3

c = 120

[d, e, f] = myfunc([6 7 3])

d = 13

e = 13

f = 126

%function  [a b c]=myfunc( x1,x2,x3,x4, ...xn)
function  [a, b, c]=myfunc( x )    % where x is an array
    a=x(1)+x(2);        % access array elements
    b=a;
    c=prod(x);          % x1*x2*x3...xn;
end 

Answer 2

[W. Feng]

The function file name is M=myfunction.m. and there are 39 inputs.

[ ]=myfunction( a, b,c, ...)

the array X with 39 values as input X=¨[x1,x2,...x39] how to execute the function only use myfunction, and X.

could we do it only use M and X to make it

feval(M(1:end-2), X)

[Chunru]

Give a concreate example.

[W. Feng]

[M_function, path1, index1]=uigetfile('*.m')

%then select the main function myfunc.m as below m.file

function [y1,y2]=myfunc (x1, x2, x3, x4,x5,x6,x7)

y1=x1+x2+x3+x4+x5+x6+x7;

y2=y1*y1;

%M_function='myfunc.m', the input was stored with

%assume Input=[1,2,3,4,5,6,7] array Input is got from other file.

%How to calculate only with Input, and M_function

%if we use

feval(M_function(1:end-2),1, 2, 3,4, 5 ,6 ,7)

% the calculation is succssful, but I just want to use such synax to use aviable Input instead of using the real value.

Answer 3

[Stephen23]

You can use a comma-separated list:

https://www.mathworks.com/help/matlab/matlab_prog/comma-separated-lists.html

https://www.mathworks.com/matlabcentral/answers/1656435-tutorial-comma-separated-lists-and-how-to-use-them

For example:

Input_data = [1,2,3,4];
C = num2cell(Input_data);
[A,B,C] = myfunc(C{:})

A = 3

B = 3

C = 24

function  [a b c]=myfunc( x1,x2,x3,x4)
a=x1+x2;
b=a;
c=x1*x2*x3*x4;
end

"The function file name is M=myfunction.m. and there are 39 inputs."

39 positional input arguments is excessive. Most likely you should rewrite the function to accept vector/array inputs, rather than lots and lots of separately-named input arguments. Most likely that would make your code simpler and more efficient, e.g. using PROD rather than repeatedly calling *, just as Chunru showed you.