[Tutor] tutorial 5.1.3

[Lloyd Kvam]

filter returns the list element if f returns true.  filter doesn't return f.

So the elements from range(2,25) are what get returned by filter.
If f(element) returns 0, then the element is omitted from the result list.

David Scott wrote:
> In the Python Tutorial (the one that comes with Python), in section 
> 5.1.3, there is something that I do not understand:
> 
>>>> def f(x): return x % 2 != 0 and x % 3 != 0
>>>
> ...
> 
>>>> filter(f, range(2, 25))
>>>
> [5, 7, 11, 13, 17, 19, 23]
> 
> That example is used to compute primes.
> 
>> From what I understand, the "return" statement is returning the tested 
>> value 
> 
> (passed in from the range) if it passes both tests. However, it seems to 
> me that the return statement would return either a 1 or a 0 and nothing 
> else, because of the "and".
> 
> return (test expression) and (test expression). If both are true, then 
> the "and" is true. else, the entire statement is false.
> 
> What am I missing or misunderstanding here?
> 
> 
> 
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Lloyd Kvam
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