Pipe in the "return" statement
ethan at stoneleaf.us
Mon Jul 25 22:07:08 CEST 2011
Billy Mays wrote:
> On 07/25/2011 10:16 AM, Archard Lias wrote:
>> On Jul 25, 2:03 pm, Ian Collins<ian-n... at hotmail.com> wrote:
>>> On 07/26/11 12:00 AM, Archard Lias wrote:
>>>> Still I dont get how I am supposed to understand the pipe and its task/
>>>> idea/influece on control flow, of:
>>>> return<statement> |<statement>
>>> It's simply a bitwise OR.
>> Yes, but how does it get determined, which one actually gets returned?
> The return statement returns a single value from a function context. The
> pipe operator takes 2 values and bitwise ORs* them together. That
> result is then returned to the caller.
Just for completeness, if the actual line had been
return <statement1> or <statement2>
then Python would compute <statement1>, and if its boolean value was
True would return the computation of <statement1>, otherwise it would
compute <statement2> and return that. When 'or' is used, the first
truthy* item is return, or the last falsey* item if none evaluate to True.
--> None or 2 or 0
--> None or 2 or 3
--> None or  or 0
With 'and', the first falsey item is returned, unless all the items are
truthy in which case the last item is returned:
--> 2 and 3
--> 2 and 0 and 9
Hope this helps.
* 'truthy' = bool(some expression or object) == True
* 'falsey' = bool(some expression or object) == False
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