[Web-SIG] htmlgen

[Gregory (Grisha) Trubetskoy]

On Thu, 30 Oct 2003, Ian Bicking wrote:

> This would solve this particular problem:
>
> class EmptyStringDict(dict):
>      def __getitem__(self, item):
>          try:
>              return dict.__getitem__(self, item)
>          except KeyError:
>              return ''

Neat trick! Here is an even more generic version:

class DefaultDict(dict):

    def __init__(self, init={}, default=""):
        self.default = default
        dict.__init__(self, init)

    def __getitem__(self, item):
        try:
            return dict.__getitem__(self, item)
        except KeyError:
            return self.default


Now I can do:

>>> "Hello %(title)s %(name)s, how are you?" % DefaultDict({'title' : 'Mr.', 'name' : 'Smith'})
'Hello Mr. Smith, how are you?'
>>>
>>> "Hello %(title)s %(name)s, how are you?" % DefaultDict({'name' : 'Smith'})
'Hello  Smith, how are you?'
>>>

Grisha