On 19 Mar 2005 11:33:20 -0800, "Kay Schluehr" <[EMAIL PROTECTED]>
wrote:
>Raymond Hettinger wrote:
>> I would like to get everyone's thoughts on two new dictionary
>methods:
>>
>> def count(self, value, qty=1):
>> try:
>> self[key] += qty
>> except KeyError:
>> self[key] = qty
>>
>> def appendlist(self, key, *values):
>> try:
>> self[key].extend(values)
>> except KeyError:
>> self[key] = list(values)
>
>-1 form me.
>
>I'm not very glad with both of them ( not a naming issue ) because i
>think that the dict type should offer only methods that apply to each
>dict whatever it contains. count() specializes to dict values that are
>addable and appendlist to those that are extendable. Why not
>subtractable, dividable or right-shiftable? Because of majority
>approval? I'm mot a speed fetishist and destroying the clarity of a
>very fundamental data structure for speedup rather arbitrary
>accumulations seems to be a bad idea. I would move this stuff in a
>subclass.
>
>Regards Kay
-1 for me too.
I agree with this. The other dictionary functions are all data
nuetral. Adding special methods to handle data should be in a
durrived class and not a built in. imho.
# Roll your own specialized dictionaries.
class NumDict( dict):
def count(self, key, qty=1):
try:
self[key] += qty
except KeyError:
self[key] = qty
def appendlist(self, key, *values):
try:
self[key].extend(values)
except KeyError:
self[key] = list(values)
mydict = NumDict()
n = 0
for k in list('abcdefg'):
n += 1
mydict[k] = n
print mydict
# {'a': 1, 'c': 3, 'b': 2, 'e': 5, 'd': 4, 'g': 7, 'f': 6}
mydict.count('c')
mydict['e'] = ['a']
mydict.appendlist('e', 'bcdef')
print mydict
# {'a': 1, 'c': 4, 'b': 2, 'e': ['a', 'bcdef'], 'd': 4, 'g': 7, 'f':
6}
This isn't that hard to do. I don't think the extra methods should be
added to the base class.
Ron
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