What value have a variable 'edit text' guide

What value have a variable 'edit text' in guide if the variable doesn't have any value in the interface......

T = str2num(get(handles.TM,'string'));

TM is a edit text in guide, but if TM doesn't have anything what value has? is for do the next:

T = str2num(get(handles.TM,'string'));

if T==[]
    T=0.001;
end

I put [] but doesn't work

Answer 1

[Geoff]

No, you need to use isempty.

if isempty(T)
  T = 0.001;
end

Note that if you use str2double instead, you'll get NaN and can use isnan to test.

[Sergio]

Thanks

Answer 2

[Walter Roberson]

T = str2double(get(handles.TM, 'string'));
if isnan(T); T = 0.001; end;

Notice str2double() instead of str2num(): this is more secure and more predictable.