Newbie: switch question in Python

[Darrell]

Instead of saving strings in the dictionary I'd save functions.
I'll demonstrate with an over the top example.
More than you wanted, I bet.

import string

def namelist(instance):
    """
    Stolen from:
    John Aycock http://www.csr.uvic.ca/~aycock/python/

    Return a list of methods for instance
    """
    namelist, classlist = [], [instance.__class__]
    dic={}
    for c in classlist:
        for b in c.__bases__:
            classlist.append(b)
        for i in dir(c):
            if not dic.has_key(i):
                dic[i]=1
                namelist.append(i)
    for k,v in instance.__dict__.items():
        if type(v)==types.FunctionType or type(v)==types.MethodType:
            namelist.append(k)
    return namelist


class Switch:
    """
    Derived classes should have methods that begin with "case_"
    and have a trailing digit. e.g. "case_55"
    These methods will be searched by the __call__ method.
    For a match on the trailing digit with val passed into __call__
    """
    def __init__(self, prefix='case_'):
        names=namelist(self)
        swDic={}
        for n in names:
            if string.find(n, prefix) != -1:
                s=string.split(n,'_')
                try:
                    key=string.atoi(s[-1])
                except ValueError:
                    raise 'Method name error. Try "case_2"'
                swDic[key]=getattr(self,n)
        self._switch=swDic

    def __call__(self, val):
        try:
            self._switch[val]()
        except KeyError:
            self.default(val)


class MySwitch(Switch):
    def __init__(self):
        Switch.__init__(self)

    def case_1(self):
        print 'Case_1'

    def case_2(self):
        print 'Case_2'

    def case_3(self):
        print 'Case_3'

    def default(self, val):
        print 'Key"%d" was found here!'%val


def test1():
    mySwtich=MySwitch()
    for x in range(5):
        mySwtich(x)


test1()
"""
Key"0" was found here!
Case_1
Case_2
Case_3
Key"4" was found here!
"""

--
--Darrell
"William J. King" <wjk at wjk.mv.com> wrote in message
news:384605BC.56EAB34E at wjk.mv.com...
> Hi again! I was reading a tutorial that said
> there was no switch statement in Python...and
> that I could use a 'conditional' if else etc.
> -- so I wrote a switch and would like to know if
> its ok to do this or if you have any other better
> ideas... Thanks to all for their help in learning
> Python in the past 2 weekends....