[python-nl] lambda rewrite question

[Wichert Akkerman]

On 06/29/2011 04:30 PM, Sylvain Viollon wrote:
> On Wed, 29 Jun 2011 16:01:38 +0200
> Floris van Manen<vm at klankschap.nl>  wrote:
>
>    Hello,
>
>> this doesn't
>> if i call the function it will return a (random?) identical value for
>> all stored lambda functions.
>>
>> def rewrite( d ):
>>      for key in d:
>>          for k in d[key]['next']:
>>              c = float(d[key]['next'][k]['prob'])
>>              d[key]['next'][k]['prob'] = lambda : c
>>      return d
>>
>>
>> There is most likely a reason to it.
>> Can someone explain me what that reason is ?
>>
>    c refer to only one variable, which scope is the function rewrite.
>
>    lambda here create a closure that return the value of this unique
>    variable, that will have as value the one computed in the last
>    iteration of your loop (that's not random).

(zullen we python-nl gewoon in het nederlands houden?)

Als workaround kan je dit herschrijven als "lambda x=c: x"

Wichert.