which one is more efficient

[Steve Holden]

Bruno Desthuilliers wrote:
> Paul Rubin a écrit :
>>> ki lo wrote:
>>>> I have type variable which may have been set to 'D' or 'E'
>>>>
>>>> Now, which one of following statements are more efficient
>>>>
>>>> if type =='D' or type == 'E':
>>>>
>>>> or
>>>>
>>>> if re.search("D|E", type):
>>>>
>>>> Please let me know because the function is going to called 10s of millions
>>>> of times.
>>> For maximum efficiency you have to use a set.
>>    if type in 'DE': ...
>>
>> might be faster.  
> 
> It might also be wrong if there's a possibility that type=='DE' :
>  >>> "DE" in "DE"
> True
> 
> 
If the "type" variable really is a type, of course, then the real 
solution is hardly radical: stop using the names of types and start 
using the types:

 >>> class D(object): pass
...
 >>> type(D)
<type 'type'>
 >>> D
<class '__main__.D'>
 >>> d = D()
 >>> type(d)
<class '__main__.D'>
 >>> class E(object): pass
...
 >>> e = E()
 >>> o = object()
 >>> for c in d, e, o:
...   print c, (type(c) in (D, E))
...
<__main__.D object at 0x7ff3150c> True
<__main__.E object at 0x7ff3156c> True
<object object at 0x7ff81478> False
 >>>

regards
  Steve
-- 
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