tkinter radiobutton

[William Gill]

I did some more digging based on your code, and discovered list 
comprehensions.  They didn't register the first time I skimmed the 
language reference and tutorial.  It's obvious the more I learn, the 
more I need to relearn what I think I know.  I need to study 
comprehensions, but they open up lots of opportunities for simpler, 
clearer code.

 >>    return row == var.get()
Oops!  I saw this as soon as I sent it, but knew you would get my point.

 > var.set(-1)
Though both ways may seem roughly equivalent today, I'd bet that in 6 
months

...
var.set(-1) # initialize as no choice
...

will be clearer.

Thanks again!

Bill

Peter Otten wrote:
> William Gill wrote:
> 
> 
>>Also, does 'row == var.get() for var in self.variables' perform the
>>comparison row == var.get() for each item in self.variables?  I would
>>have had to write:
>>
>>for var in self.variables:
>>    return row == var.get()
> 
> 
> Or rather
> 
> result = []
> for var in self.variables:
>     result.append(row == var.get())
> return tuple(result)
> 
> This can be rewritten to a 'list comprehension'
> 
> return tuple([row == var.get() for var in self.variables])
> 
> and, since Python 2.4, to the 'generator expression' that I used and which
> avoids building the intermediate list. Both constructs also feature an
> if-clause, see
> 
> http://docs.python.org/tut/node7.html#SECTION007140000000000000000
> http://docs.python.org/tut/node11.html#SECTION00111100000000000000000
> 
> 
>>p.s.  I tweaked
>>
>>rbn = tk.Radiobutton(self, text=text, variable=var, value=y)
>>to
>>rbn = tk.Radiobutton(self, text=text, variable=var, value=y+1)
>>
>>and
>>
>>return tuple(row == var.get() for var in self.variables)
>>to
>>return tuple(row+1 == var.get() for var in self.variables)
>>
>>so that the Radiogrid doesn't initialize w/row 1 selected, and
>>accomodates cases where nothing is selected in any column.
> 
>  
> Another option would have been to initialize the variables
> 
> ...
> var = tk.IntVar()
> var.set(-1)
> if trace_write:
> ...
> 
> Peter
>