Local Functions
This topic explains the term local function, and shows how to create and use local functions.
MATLAB program files can contain code for more than one function. In a function file, the first
function in the file is called the main function. This function is visible to functions in other files, or
you can call it from the command line. Additional functions within the file are called local functions,
and they can occur in any order after the main function. Local functions are only visible to other
functions in the same file. They are equivalent to subroutines in other programming languages, and
are sometimes called subfunctions.
As of R2016b, you can also create local functions in a script file, as long as they all appear after the
last line of script code. For more information, see “Add Functions to Scripts” on page 18-12.
For example, create a function file named mystats.m that contains a main function, mystats, and
two local functions, mymean and mymedian.
function [avg, med] = mystats(x)
n = length(x);
avg = mymean(x,n);
med = mymedian(x,n);
end
function a = mymean(v,n)
% MYMEAN Example of a local function.
a = sum(v)/n;
end
function m = mymedian(v,n)
% MYMEDIAN Another example of a local function.
w = sort(v);
if rem(n,2) == 1
m = w((n + 1)/2);
else
m = (w(n/2) + w(n/2 + 1))/2;
end
end
The local functions mymean and mymedian calculate the average and median of the input list. The
main function mystats determines the length of the list n and passes it to the local functions.
Although you cannot call a local function from the command line or from functions in other files, you
can access its help using the help function. Specify names of both the file and the local function,
separating them with a > character:
help mystats>mymean
mymean Example of a local function.
Local functions in the current file have precedence over functions in other files. That is, when you call
a function within a program file, MATLAB checks whether the function is a local function before
looking for other main functions. Therefore, you can create an alternate version of a particular
function while retaining the original in another file.
Local Functions
20-25
This topic explains the term local function, and shows how to create and use local functions.
MATLAB program files can contain code for more than one function. In a function file, the first
function in the file is called the main function. This function is visible to functions in other files, or
you can call it from the command line. Additional functions within the file are called local functions,
and they can occur in any order after the main function. Local functions are only visible to other
functions in the same file. They are equivalent to subroutines in other programming languages, and
are sometimes called subfunctions.
As of R2016b, you can also create local functions in a script file, as long as they all appear after the
last line of script code. For more information, see “Add Functions to Scripts” on page 18-12.
For example, create a function file named mystats.m that contains a main function, mystats, and
two local functions, mymean and mymedian.
function [avg, med] = mystats(x)
n = length(x);
avg = mymean(x,n);
med = mymedian(x,n);
end
function a = mymean(v,n)
% MYMEAN Example of a local function.
a = sum(v)/n;
end
function m = mymedian(v,n)
% MYMEDIAN Another example of a local function.
w = sort(v);
if rem(n,2) == 1
m = w((n + 1)/2);
else
m = (w(n/2) + w(n/2 + 1))/2;
end
end
The local functions mymean and mymedian calculate the average and median of the input list. The
main function mystats determines the length of the list n and passes it to the local functions.
Although you cannot call a local function from the command line or from functions in other files, you
can access its help using the help function. Specify names of both the file and the local function,
separating them with a > character:
help mystats>mymean
mymean Example of a local function.
Local functions in the current file have precedence over functions in other files. That is, when you call
a function within a program file, MATLAB checks whether the function is a local function before
looking for other main functions. Therefore, you can create an alternate version of a particular
function while retaining the original in another file.
Local Functions
20-25