Accidentally overrode 'filter' function, how can I get it back?

I accidentally overrode the 'filter' function by making a user defined function also named 'filter'.

I tried to clear it by doing

builtin('function')

but that just got me an error:

'Error using filter

Not enough input arguments.'

How can I make sure I have the builtin 'filter' function back?

Answer 1

[Star Strider]

It’s probably still there.

first run this line from a script or your Command Window:

which filter -all

When I ran it, I got:

built-in (C:\Program Files\MATLAB\R2019a\toolbox\matlab\datafun\filter)
filter is a Java method                                                            % Shadowed java.util.Locale method
filter is a built-in method                                                        % Shadowed connector.internal.LoggerLevel method
filter is a built-in method                                                        % Shadowed matlab.lang.OnOffSwitchState method
filter is a built-in method                                                        % Shadowed matlab.internal.lang.capability.Capability method
C:\Program Files\MATLAB\R2019a\toolbox\matlab\bigdata\@tall\filter.m               % Shadowed tall method
C:\Program Files\MATLAB\R2019a\toolbox\simulink\simulink\@SigLogSelector\filter.m  % Shadowed SigLogSelector method
C:\Program Files\MATLAB\R2019a\toolbox\fixedpoint\fixedpointtool\@fxptui\filter.m  % Shadowed fxptui method
C:\Program Files\MATLAB\R2019a\toolbox\matlab\timeseries\@timeseries\filter.m      % Shadowed timeseries method

Then try it with an example from the documentation for filter and see if it still works (after you rename your function named ‘filter’ to something that doesn’t ‘overshadow’ the builtin function).