GUI Text box

In my GUI I have a text box where the input looks like x(n)=5*rand(1,1)+x(n); , In my m-file code I get the written statement from the textbox by writing eval(get(handles.textbox,'string')); . Is there a way that the input to my textbox will only be 5*rand(1,1)+x(n); and in my m-file I have x(n)=(something to call the string from textbox). I tired x(n)=eval(get(handles.textbox,'string')); and it does not work.

Let me know if I'm not being clear.

[Andy]

Could you be more clear about what doesn't work? Is there an error? If so, post the message. Does it give unexpected output? If so, post the output and tell us the expected output.

Answer 1

[Matt Fig]

S = get(handles.textbox,'string'); % S = 'x(n)=5*rand(1,1)+x(n)'
S = S(6:end)
x(n) = eval(S)

Or, more generally,

S = get(handles.textbox,'string'); % S = 'x(n)=5*rand(1,1)+x(n)'
S = regexprep(S,'(?==)','');
x(n) = eval(S)

This takes away everything up to and including the equals sign.

Answer 2

[Andy]

Well, I suppose you could do something like

eval(['x(n)=' get(...)]);

Or you could use evalin:

doc evalin

But eval is pretty dangerous. You're letting your user execute arbitrary code.