Python Pseudo-Switch

[Dan Bishop]

James Stroud wrote:
> Hello All,
>
> Because of my poorly designing a database, I have recently found it
necessary
> to explore the wonders of the Python pseudo-switch:
>
> do_case = { "A" : lambda x: x["bob"],
>             "B" : lambda x: x["carol"],
>             "C" : lambda x: "Ted",
>             "D" : lambda x: do_something(x) }
>
> my_thing = do_case[get_value_from_thin_air()](adict)
>
>
> How to handle this kind of thing when lambda is removed from the
language,
> beside the obvious def'ing those tiny little functions?

You can always re-invent lambda.

>>> def lambda2(arg_names, expression):
...    exec 'def _(%s): return %s' % (','.join(arg_names), expression)
...    return _
...
>>> add = lambda2(('x', 'y'), 'x + y')
>>> add(3, 4)
7