Hi list,
I'm trying to understand how to use a class-level dictionary to act as a switch
for class methods. In the contrived example below, I have the statistic name
as the key and the class method as the value.
class Statistics(object):
STAT = {
'MEAN': get_mean,
'SUM': get_sum,
}
def __init__(self, a, b):
self.a = a
self.b = b
def get_mean(self):
return (self.a + self.b) / 2.0
def get_sum(self):
return (self.a + self.b)
def get_stat(self, stat):
f = self.STAT[stat.upper()]
return f(self)
if __name__ == '__main__':
spam = Statistics(4, 3)
print spam.get_stat('mean')
print spam.get_stat('sum')
When I try to run this, I get:
NameError: name 'get_mean' is not defined
If I move the STAT dictionary to the bottom of the class, it works fine. I
understand why I get an error, i.e. when the dictionary is created get_mean
hasn't yet been defined, but I'm wondering if there is a better common practice
for doing this type of lookup. My web searches didn't come up with anything
too applicable.
thanks, matt
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