Python create own dict view of subset of dictionary

Question

As the many questions on the topic here on SO attest, taking a slice of a dictionary is a pretty common task, with a fairly nice solution:

{k:v for k,v in di         


        

Answer 1

To clarify the semantics, you're thinking of something like this:?

class FilteredDictView:
    def __init__(self, base_dict, test):
        self._base_dict = base_dict
        self._test = test
    def __getitem__(self, key):
        value = self._base_dict[key] # might throw KeyError
        if not self._test(key,value):
            throw KeyError(key)
        return value
    # ... implement remaining dict-like-methods ...

If so, then I don't know of any such third party class. If you want to make implementing the remaining methods a little easier, you might look at using "UserDict" as a base class, which is basically just a wrapper for dict (the "UserDict.data" attribute is used to store the wrapped dict).