Is it possible to define more than one function per file in MATLAB and access them from outside that file

Question

When I was studying for my undergraduate degree in EE  MATLAB required each function to be defined in its own file  even if it was a one-liner   I m studying for a graduate degree now  and I have to write a project in MATLAB  Is this still a requirement for newer versions of MATLAB   If it is possible to put more than one function in a file  are there any restrictions to this  For instance  can all the functions in the file be accessed from outside the file  or only the function that has the same name as the file   Note  I am using MATLAB release R2007b

User · Answer

You could also group functions in one main file together with the main function looking like this:

function [varargout] = main( subfun, varargin )
[varargout{1:nargout}] = feval( subfun, varargin{:} ); 

% paste your subfunctions below ....
function str=subfun1
str='hello'

Then calling subfun1 would look like this: str=main('subfun1')

User · Answer

I really like SCFrench s answer - I would like to point out that it can easily be modified to import the functions directly to the workspace using the assignin function   Doing it like this reminds me a lot of Python s  import x from y  way of doing things   function message   makefuns   assignin  base   fun1   fun1     assignin  base   fun2   fun2     message  Done importing functions to workspace   end  function y fun1 x    y x  end  function z fun2   z 1  end   And then used thusly    gt  gt  makefuns ans   Done importing functions to workspace   gt  gt  fun1 123  ans      123   gt  gt  fun2   ans        1

User · Answer

The first function in an m-file  i e  the main function   is invoked when that m-file is called  It is not required that the main function have the same name as the m-file  but for clarity it should  When the function and file name differ  the file name must be used to call the main function   All subsequent functions in the m-file  called local functions  or  subfunctions  in the older terminology   can only be called by the main function and other local functions in that m-file  Functions in other m-files can not call them  Starting in R2016b  you can add local functions to scripts as well  although the scoping behavior is still the same  i e  they can only be called from within the script    In addition  you can also declare functions within other functions  These are called nested functions  and these can only be called from within the function they are nested  They can also have access to variables in functions in which they are nested  which makes them quite useful albeit slightly tricky to work with   More food for thought     There are some ways around the normal function scoping behavior outlined above  such as passing function handles as output arguments as mentioned in the answers from SCFrench and Jonas  which  starting in R2013b  is facilitated by the localfunctions function   However  I wouldn t suggest making it a habit of resorting to such tricks  as there are likely much better options for organizing your functions and files   For example  let s say you have a main function A in an m-file A m  along with local functions D  E  and F  Now let s say you have two other related functions B and C in m-files B m and C m  respectively  that you also want to be able to call D  E  and F  Here are some options you have    Put D  E  and F each in their own separate m-files  allowing any other function to call them  The downside is that the scope of these functions is large and isn t restricted to just A  B  and C  but the upside is that this is quite simple  Create a defineMyFunctions m-file  like in Jonas  example  with D  E  and F as local functions and a main function that simply returns function handles to them  This allows you to keep D  E  and F in the same file  but it doesn t do anything regarding the scope of these functions since any function that can call defineMyFunctions can invoke them  You also then have to worry about passing the function handles around as arguments to make sure you have them where you need them  Copy D  E and F into B m and C m as local functions  This limits the scope of their usage to just A  B  and C  but makes updating and maintenance of your code a nightmare because you have three copies of the same code in different places  Use private functions  If you have A  B  and C in the same directory  you can create a subdirectory called private and place D  E  and F in there  each as a separate m-file  This limits their scope so they can only be called by functions in the directory immediately above  i e  A  B  and C  and keeps them together in the same place  but still different m-files    myDirectory      A m     B m     C m     private          D m         E m         F m    All this goes somewhat outside the scope of your question  and is probably more detail than you need  but I thought it might be good to touch upon the more general concern of organizing all of your m-files

User · Answer

I define multiple functions in one  m file with Octave and then use the command from within the  m file where I need to make use of the functions from that file   source  mycode m      Not sure if this is available with Matlab   octave 8 gt  help source  source  is a built-in function   -- Built-in Function   source  FILE       Parse and execute the contents of FILE   This is equivalent to      executing commands from a script file  but without requiring the      file to be named  FILE m

User · Answer

The only way to have multiple  separately accessible functions in a single file is to define STATIC METHODS using object-oriented programming  You d access the function as myClass static1    myClass static2   etc    OOP functionality is only officially supported since R2008a  so unless you want to use the old  undocumented OOP syntax  the answer for you is no  as explained by  gnovice   EDIT   One more way to define multiple functions inside a file that are accessible from the outside is to create a function that returns multiple function handles  In other words  you d call your defining function as  fun1 fun2 fun3  defineMyFunctions  after which you could use out1 fun1 inputs  etc

User · Answer

Along the same lines as SCFrench s answer  but with a more C  style spin    I would  and often do  make a class containing multiple static methods  For example   classdef Statistics      methods Static          function val   MyMean data              val   mean data           end          function val   MyStd data              val   std data           end     end  end   As the methods are static you don t need to instansiate the class  You call the functions as follows   data   1 10   mean   Statistics MyMean data   std   Statistics MyStd data

User · Answer

As of R2017b  this is not officially possible  The relevant documentation states that   Program files can contain multiple functions  If the file contains only function definitions  the first function is the main function  and is the function that MATLAB associates with the file name  Functions that follow the main function or script code are called local functions  Local functions are only available within the file   However  workarounds suggested in other answers can achieve something similar

User · Answer

I have try with the SCFRench and with the Ru Hasha on octave   And finally it works  but I have done some modification  function message   makefuns     assignin  base   fun1    fun1       Ru Hasha     assignin  base    fun2    fun2      Ru Hasha     message fun1  fun1                  SCFrench     message fun2  fun2                  SCFrench end  function y fun1 x      y x  end  function z fun2     z 1  end   Can be called in other  m  file   printf   d n   makefuns fun1 123    printf   d n   makefuns fun2       update    I added an answer because neither the  72 nor the  20 worked in octave for me  The one I wrote works perfectly  and I tested it last Friday when I later wrote the post

User · Answer

Generally  the answer to your question is no  you cannot define more than one externally visible function per file  You can return function handles to local functions  though  and a convenient way to do so is to make them fields of a struct  Here is an example   function funs   makefuns   funs fun1  fun1    funs fun2  fun2  end  function y fun1 x    y x  end  function z fun2   z 1  end   And here is how it could be used    gt  gt  myfuns   makefuns   gt  gt  myfuns fun1 5      ans        5  gt  gt  myfuns fun2        ans        1

[matlab] Is it possible to define more than one function per file in MATLAB, and access them from outside that file?

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