functional programming and default parameters

Tim Peters tim.one at home.com
Fri Jun 29 10:04:08 CEST 2001


[Nick Perkins, tries assorted ways to make a list of functions s.t.

> fns[0]() -> 0
> fns[1]() -> 1
> fns[2]() -> 2
> etc.

but without abusing default arguments]

Here's one easy way:

>>> from __future__ import nested_scopes
>>> def makefunc(i):
...     return lambda: i
>>> fns = [makefunc(i) for i in range(10)]
>>> fns[5]()
5
>>> fns[2]()
2
>>>

etc.  Without nested scopes, you may have to resort to eval (or exec in
fancier contexts):

>>> fns = [eval("lambda: %d" % i) for i in range(10)]
>>> fns[5]()
5
>>> fns[2]()
2
>>

etc.





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