varargout - Variable-length output argument list - MATLAB (original) (raw)

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Variable-length output argument list

Syntax

Description

varargout is an output variable in a function definition statement that enables the function to return any number of output arguments. Specify varargout using lowercase characters, and include it as the last output argument after any explicitly declared outputs.

When the function executes, varargout is a 1-by-N cell array, where N is the number of outputs requested after the explicitly declared outputs. Inside of a function,varargout is an uninitialized variable and is not preallocated.

example

Examples

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Define a function in a file named returnVariableNumOutputs.m that returns an output size vector s and a variable number of additional outputs.

type returnVariableNumOutputs

function [s,varargout] = returnVariableNumOutputs(x) nout = max(nargout,1) - 1; s = size(x); for k = 1:nout varargout{k} = s(k); end end

Output s contains the dimensions of the input array x. Additional outputs correspond to the individual dimensions within s.

Call the function with a three-dimensional array and request three outputs.

A = rand(4,5,2); [s,rows,cols] = returnVariableNumOutputs(A)

Call the function again with a four-dimensional array and request four outputs. This time, the function does not return the individual fourth dimension.

A = zeros(1,4,5,2); [s,dim1,dim2,dim3] = returnVariableNumOutputs(A)

Call the function once more on A and request one output. Now the function returns the dimensions of A and not varargout.

s = returnVariableNumOutputs(A)

Define a function in a file named variableNumInputAndOutput.m that accepts a variable number of inputs and outputs.

type variableNumInputAndOutput

function varargout = variableNumInputAndOutput(varargin) disp(['Number of provided inputs: ' num2str(length(varargin))]) disp(['Number of requested outputs: ' num2str(nargout)])

for k = 1:nargout
    varargout{k} = k;
end

end

Call the function with two inputs and three outputs.

[d,g,p] = variableNumInputAndOutput(6,'Nexus')

Number of provided inputs: 2 Number of requested outputs: 3

Call the function again with no inputs or outputs.

variableNumInputAndOutput

Number of provided inputs: 0 Number of requested outputs: 0

Extended Capabilities

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Usage notes and limitations:

• For code generation, to use varargout in an entry-point (top-level) function, you must specify the number of output parameters by using the codegen -nargout syntax.
• The index into varargout must be a compile-time constant.

Version History

Introduced before R2006a