MATLAB Answers

Getting first element of a function output

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Yue
Yue on 18 May 2012
Commented: Fabien Fellay on 16 Jul 2020
Hi everyone,
I am trying to get the value of the first element of an output of a function. For example, The output of my function test is [a1, a2, a3] and I want to get the value of a1 only.
The way I do it is
a = test(input);
result = a(1);
I wonder if there is an easier way to do it. Is there something similar to
result = (test(input))(1);
in matlab?
  1 Comment
Fabien Fellay
Fabien Fellay on 16 Jul 2020
Now, you can do (the less painful solution so far):
result = table(test(input)).Var1(1);
For example, if you want to do:
A = magic(3);
result = A(2,2);
You can do:
result = table(magic(3)).Var1(2,2);
The following is also possible (but longer and ugly):
result = subsref(magic(3),struct('type','()','subs',{{2,2}}));

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Answers (2)

Andrei Bobrov
Andrei Bobrov on 18 May 2012
no easier way
result = subsref(test(input),struct('type','()','subs',{{1}}))

Daniel Shub
Daniel Shub on 18 May 2012
See this answer about what is missing from MATLAB.
If test is a function you wrote, you could change what it returns. You could also write a wrapper around test:
function a1 = test1(input)
a = test(input);
result = a(1);
end
  1 Comment
Jan
Jan on 18 May 2012
In my opinion this method is easy, clear and efficient.
A modification of the Matlab syntax would be worse due to breaking the backward compatibility. +1

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