Question on sort() key function

[Marc 'BlackJack' Rintsch]

On Tue, 22 Jan 2008 09:56:55 +0000, Robert Latest wrote:

> Peter Otten wrote:
>> Robert Latest wrote:
>>
>> This should work then:
>>
>> def date_key(f):
>>     return f.mod_date.toordinal()
>> flist.sort(key=date_key)
>>
>> This can also be written as
>>
>> flist.sort(key=lambda f: f.mod_date.toordinal())
> 
> Well, that's almost Paul's (non-working) suggestion above, but it works 
> because of the parentheses after toordinal. Beats me how both versions can 
> be valid, anyway.
> 
> To me it's all greek. I grew up with C function pointers, and they 
> always work.
> 
> robert

Suppose `func` is a C function pointer, then

  foo = func;

and

  foo = func();

have different meanings.  It's just the same in Python.  First is the
function itself, second *calls* the function.

Ciao,
	Marc 'BlackJack' Rintsch