python - Check if items in a list exist in dictionary -

my question might little complicated understand here's thing. have nested dictionary looks this:

dict_a = {'one': {'bird':2, 'tree':6, 'sky':1, 'total':9},           'two': {'apple':3, 'sky':1, 'total':4},           'three': {'tree':6, 'total':6},           'four': {'nada':1, 'total':1},           'five': {'orange':2, 'bird':3, 'total':5}           } 

and list:

list1 = ['bird','tree'] newlist = [] 

how can check items in list1 whether in nested dictionary of dict_a , append newlist? output should this:

newlist = ['one','three','five'] 

since bird , tree happened in nested dictionary of one, 3 , five.

what can think of is:

for s,v in dict_a.items():     s1,v1 in v.items():         item in list1:             if item == s1:                newlist.append(s) 

make list1 set , use dictionary views, , list comprehension:

set1 = set(list1) newlist = [key key, value in dict_a.iteritems() if value.viewkeys() & set1] 

in python 3, use value.keys() , dict_a.items instead.

this tests if there set intersection between dictionary keys , set of keys looking (an efficient operation).

demo:

>>> dict_a = {'one': {'bird':2, 'tree':6, 'sky':1, 'total':9}, ...           'two': {'apple':3, 'sky':1, 'total':4}, ...           'three': {'tree':6, 'total':6}, ...           'four': {'nada':1, 'total':1}, ...           'five': {'orange':2, 'bird':3, 'total':5} ...           } >>> set1 = {'bird','tree'} >>> [key key, value in dict_a.iteritems() if value.viewkeys() & set1] ['three', 'five', 'one'] 

note dictionary ordering arbitrary (depending on keys used , dictionary insertion , deletion history), output list order may differ.

technically speaking, can use list directly (value.viewkeys() & list1 works) making set states intention more clearly.