Python Pseudo-Switch

[Jason Mobarak]

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) }
>

class CaseThing:
  def pref_A (self, x):
    return x["bob"]
  def pref_B (self, x):
    return x["carol"]
  def pref_C (self, x);
    return "Ted"
  def pref_D (self, x)
    return do_something(x)
  def getThing (self, x):
    attr = getattr(self, 'pref_%s' % (x,))
    if attr is not None:
      return attr
    else:
      raise SomeError("Thing %s does not exist" % (x,))

my_thing = CaseThing().getThing(get_value_from_thin_air)(adict)

You can do something similar with method decorators for more complex
strings than what's allowed for python method names.

> 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?
>
> James
>
> --
> James Stroud
> UCLA-DOE Institute for Genomics and Proteomics
> Box 951570
> Los Angeles, CA 90095
> 
> http://www.jamesstroud.com/