使用defaultdict搜索键/值

Question

I'm familiar with the use of the iteritems() and items() use with the standard dictionary which can be coupled with a for loop to scan over keys and values. However how can I best do this with the default dict. For example, I'd like to check that a given value does not show up in either the key or any of the values associated with any key. I'm currently trying the following:

for key, val in dic.iteritems():
    print key, val

however I get the following:

1 deque([2, 2])

and I have the following declarations for the variables/dictionary

from collections import defaultdict, deque
clusterdict = defaultdict(deque)

So how do I best get at key values? Thanks!

Answer 1

In general, for a defaultdict dd , to check whether a value x is used as a key do this:

x in dd

To check whether x is used as a value do this:

x in dd.itervalues()

In your case (a defaultdict with deques as values), you may want to see whether x is in any of the deques:

any(x in deq for deq in dd.itervalues())

Remember, defaultdicts behave like regular dictionaries except that they create new entries automatically when doing d[k] lookups on missing keys; otherwise, they behave no differently than regular dicts.

Answer 2

If I understood your question:

for key, val in dic.iteritems():
    if key!=given_value and not given_value in val:
        print "it's not there!"

Unless you meant something else...

Answer 3

I made this for Python 3:

from collections import defaultdict

count_data = defaultdict(int)
count_data[1] = 10
query = 2
if query in count_data.values():
   print('yes')

Edit

You can use Counter dictionary too:

from collections import Counter
count_data = Counter()
count_data[1] = 10
query = 2
if query in count_data.values():
    print('yes')

Answer 4

stuff = 'value to check'
if not any((suff in key or stuff in  value) for key, value in dic.iteritems()):
    # do something if stuff not in any key or value

Answer 5

http://docs.python.org/library/collections.html#collections.defaultdict

So you can use iteritems