Save the output of a function - matlab

Question

I have been able to put together the following code to find a time stamp every time space bar is pressed. However, I can't figure out a way to save the S.tm to the work space. Here is the code:
function main
S.tm = [];
S.cnt = 0;
S.fh = figure('KeyPressFcn',#youPressedSomething,...
'menu','none',...
'pos',[400 400 320 50]);
S.th = uicontrol('Style','text','Position',[10 10 300 30],...
'String','You have not hit space yet');
function youPressedSomething(varargin)
if strcmp(varargin{2}.Character,' ')
S.tm = [S.tm now]
S.cnt = S.cnt + 1;
set(S.th,'str',sprintf('You hit space %i!',S.cnt));
end
end
end

Answer 1

There are two main options here. You could use assignin within your function to save the data to the main workspace.
function main
S.tm = [];
S.cnt = 0;
S.fh = figure('KeyPressFcn',#youPressedSomething,...
'menu','none',...
'pos',[400 400 320 50]);
S.th = uicontrol('Style','text','Position',[10 10 300 30],...
'String','You have not hit space yet');
function youPressedSomething(varargin)
if strcmp(varargin{2}.Character,' ')
S.tm = [S.tm now]
S.cnt = S.cnt + 1;
set(S.th,'str',sprintf('You hit space %i!',S.cnt));
%// Save as "timestamps" in the base workspace
assignin('base', 'timestamps', S.tm);
end
end
end
Or a better approach would be to use waitfor to block execution of the function until the figure is closed. Then you can return S.tm just like a normal output argument
function timestamps = main()
S.tm = [];
S.cnt = 0;
S.fh = figure('KeyPressFcn',#youPressedSomething,...
'menu','none',...
'pos',[400 400 320 50]);
S.th = uicontrol('Style','text','Position',[10 10 300 30],...
'String','You have not hit space yet');
%// Wait until the figure is closed
waitfor(S.fh);
%// Save S.tm as timestamps and return
timestamps = S.tm;
function youPressedSomething(varargin)
if strcmp(varargin{2}.Character,' ')
S.tm = [S.tm now]
S.cnt = S.cnt + 1;
set(S.th,'str',sprintf('You hit space %i!',S.cnt));
%// Save as "timestamps" in the base workspace
assignin('base', 'timestamps', S.tm);
end
end
end

Answer 2

You can try to edit your code this way:
function[S.fh]=main()
%% Your Code
function yPS(varargin)
if...
%% Your Code
end
set(S.fh,'UserData',S.tm);
end %yPS
end %main
This should return figure handle to the workspace and keep it in memory as well. Then whenever the yPS function is called it uses shared handle S.fh to the figure and (re)sets UsedData property which is dedicated to contain, well, user data.
To use the function call it Foo=main.
get(Foo.fh,'UserData')
ans =
[]
Hit spacebar several times
>> get(AA.fh,'userdata')
ans =
1.0e+005 *
7.3645
7.3645
7.3645