lyst[:None]

[Anton Muhin]

Jacek Generowicz wrote:
> Given that the name lyst refers to a list, I'd like to limit the
> number of elements returned by the slice
> 
>   lyst[:limit]
> 
> by setting the value of limit.
> 
> Now, what if I want to include the option of getting all the elements
> from the list? Is there a value of limit which would lead to the
> desired behaviour?
> 
> -1 does not work: the upper limit is exclusive, so the last element is
> left out
> 
> -0 does not work: it just evaluates to 0
> 
> None does not work: subscripts must be integers
> 
> Is there a way of doing this on one line?
> 
> (Yes, I know I can split it up onto several lines, and probably should
> if I want humans to understand the code ...)

I might be missing something, but still I would prefer:

def get_elements(l, count = None):
     if count:
         return l[:count]
     else:
         return l[:]

hth,
anton.