python get number of occurences of given pattern in a dict

Question

I have a dictionary as following:

adict = {'instr1' : "yes", 'instr2' : "yes", 'instr3' : "yes", 'instr4' : "no"}

Is there an easy method to get the number of "yes" in the dictionary?

Answer 1

You can use collections.Counter :

>>> adict = {'instr1' : "yes", 'instr2' : "yes", 'instr3' : "yes", 'instr4' : "no"}
>>> import collections
>>> collections.Counter(adict.values())
Counter({'yes': 3, 'no': 1})

Answer 2

You can use sum and a generator expression:

>>> sum(1 for x in adict.itervalues() if x == 'yes')
3

As True == 1 , so this is also valid:

sum( x == 'yes' for x in adict.itervalues())

Another option is list.count , this is going to be fast compared to sum() , but creates a list of all values in the memory:

>>> adict.values().count('yes')
3