Question

Given a dictionary keyed by 2-element tuples, I want to return all the key-value pairs whose keys contain a given element.

For example, the dictionary can be:

tupled_dict = {('a',1):1, ('a',2):0, ('b',1):1, ('c',4):0}

and the given element is 'a', then the key-value pairs that should be returned would be:

('a',1):1, ('a',2):0

What is the fastest code to do this?

EDIT:

In addition, as a related sub-question, I am interested in the fastest way to delete all such key-value pairs given an element of the keys. Obviously, once I have the results of the above, I can use a loop to delete each dictionary item one by one, but I wonder if there is a short-cut way to do it.

Answer 1

To get those ones:

>>> {k: v for k, v in tupled_dict.iteritems() if 'a' in k}
{('a', 1): 1, ('a', 2): 0}

Similarly, to delete the other ones:

>>> tupled_dict = {k: v for k, v in tupled_dict.iteritems() if 'a' not in k}
>>> tupled_dict
{('b', 1): 1, ('c', 4): 0}