To avoid global variables, which is the best way to share variables among functions in a GUI in Matlab:

1: Using setappdata/getappdata

2: Populating a structure other than 'handles' and then passing this structure as an argument to the functions

3: Populating 'handles' with multiple parameters and using it wherever required

4: Others ?

Is there a limit to the extent 'handles' can be populated with user data in a gui in matlab, ie is it advisable to keep populating the same structure(handles or user-defined) with any number of parameters

Answer 1

[Stephen23]

I recommend using nested functions: simple, intuitive, easy to debug. See my FEX submission iregexp for an example of this:

https://www.mathworks.com/matlabcentral/fileexchange/48930-interactive-regular-expression-tool

Note how it combines nested functions, local functions, several callbacks, and no globals anywhere!