lambda in list comprehension acting funny

Alister alister.ware at ntlworld.com
Thu Jul 12 11:44:15 CEST 2012


On Wed, 11 Jul 2012 08:43:11 +0200, Daniel Fetchinson wrote:

>> funcs = [ lambda x: x**i for i in range( 5 ) ]
>> print funcs[0]( 2 )
>> print funcs[1]( 2 )
>> print funcs[2]( 2 )
>>
>> This gives me
>>
>> 16 16 16
>>
>> When I was excepting
>>
>> 1
>> 2
>> 4
>>
>> Does anyone know why?
> 
> And more importantly, what's the simplest way to achieve the latter? :)

Having read Steve's explanation in the other thread (which I think has 
finally flipped the light switch on lambda for me) it only requires a 
minor change

funcs=[ lambda x,y=i:x**y for i in range(5) ]

although I cant actually think why this construct would be needed in 
practice, how are you actually using it


-- 
* Simunye is so happy she has her mothers gene's
<Dellaran> you better give them back before she misses them!



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