On Oct 29, 4:28 pm, Terry Reedy <[EMAIL PROTECTED]> wrote:
> John Townsend wrote:
> > I’m trying to figure out how to use filter to walk through a list.
>
> > If I try a simple scripts like this:
>
> > def greaterthanten (number):
> > #pdb.set_trace()
> > if (number > 10):
> > ret_val = 1
>
> > else:
> > ret_val = 0
>
> > return ret_val
>
> > old_list = [1,2,20,30,5]
>
> > new_list = filter(greaterthanten, old_list)
>
> > #new_list becomes [20, 30]
>
> > The script works as I would expect. However, what if I need to pass more
> > than one argument to the function? Can I do that with filter? Or does
> > filter work only with function that take only a single arg?
That single argument could be a list.
>>> old_list = [1,2,20,30,5]
>>> def power_of_10(a):
if a[0]%10==0 and a[0]<a[1]:
return True
else:
return False
>>> new_list = [i[0] for i in filter(power_of_10,[[i,the_limit] for i in
>>> old_list])]
>>> new_list
[20, 30]
>>> the_limit = 25
>>> new_list = [i[0] for i in filter(power_of_10,[[i,the_limit] for i in
>>> old_list])]
>>> new_list
[20]
>
> The latter. Other functions could be wrapped to bind all parameters
> except the list element. Or write an explicit loop.- Hide quoted text -
>
> - Show quoted text -
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