how do i obtain several output with a "function" function?

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raffaele 2014-10-28

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回答： Chad Greene 2014-10-28

Hi everybody, I have a question. My goal is to write a function as the following function[beta] = myfunction (x,y) where beta is a vector k-by-1, x is a n-by-k matrix and y is a n-by-1 vector. Now the length of beta is given by the length k of the x matrix, so its output changes for different length of x. What I want is to save the function and then use it as normal: [beta]=myfunction(x,y) but, instead of showing as result a vector of n elements, I would as output n numbers, one each row of beta, and call them "beta1", "beta2", ... , "beta i". If possible I would not write the code: function[beta1, beta2, ...], since the number of output changes depending on x. How can I write my function?

(If I was not clear in my explaination, what I want is this: [beta]=myfunction(x,y) beta1= .... beta2= .... ... ... beta i= .... )

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Answer 1

Chad Greene 2014-10-28

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An example of varargout is described here.

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Answer 2

James Tursa 2014-10-28

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编辑：James Tursa 2014-10-28

Please see this related post:

http://www.mathworks.com/matlabcentral/answers/57445-faq-how-can-i-create-variables-a1-a2-a10-in-a-loop

The bottom line is don't do this, it will only create programming headaches downstream for you. Learn to use indexing or cell arrays or some other method that is much friendlier to good programming practices.

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James Tursa 2014-10-28

编辑：James Tursa 2014-10-28

You can do this using varargout constructs, and programatically return a variable number of outputs. But you would also need to capture these multiple outputs in the calling statement. The specific names beta1, beta2, etc at the calling level would not be determined by your function itself (which would be returning everything in the varargout cell array as varargout{1}, varargout{2}, etc), but would be determined by the calling statement (as is the case with all function calls in MATLAB, no different here) e.g. with an eval statement. Again, I would not advise this. What is the advantage of using beta1, beta2, etc in your code vs simple indexing?

raffaele 2014-10-28

编辑：raffaele 2014-10-28

在 MATLAB Online 中打开

actually the name doesn't matter much.. I wanted only a way to transform: [beta]=f(x,y) beta =

   -0.2496    0.4994   -0.4997    0.3175   -1.4716    0.9725
1894    0.2544    8.6052    0.0001    1.5668    2.8120
4884    0.3106   11.2301    0.0000    2.7283    4.2484
1548    0.6933    1.6658    0.0734   -0.5415    2.8512

into: [beta]=f(x,y)

out1 -0.2496 0.4994 -0.4997 0.3175 -1.4716 0.9725

out2 2.1894 0.2544 8.6052 0.0001 1.5668 2.8120

out3 3.4884 0.3106 11.2301 0.0000 2.7283 4.2484

out4 1.1548 0.6933 1.6658 0.0734 -0.5415 2.8512

It doesn't matter the name of the outputs, I just want to obtain multiple outputs arguments from a single output in square brackets "[...]=function(..)", since, as I've said before, the number of outputs can change depending on x

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