how to use an array as the input variable for function

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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

Risposta accettata

Chunru
Chunru il 20 Lug 2022
% 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

Più risposte (2)

W. Feng
W. Feng il 20 Lug 2022
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)
  2 Commenti
W. Feng
W. Feng il 20 Lug 2022
[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.

Accedi per commentare.


Stephen23
Stephen23 il 20 Lug 2022
Modificato: Stephen23 il 20 Lug 2022
You can use a comma-separated list:
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.

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