I\'ve been trying to solve this program which takes two strings as input and outputs number of common letters. For Example, if the input was \"common\" and \"connor\" then t
you can do list comprehension for that too
>>> a = 'common'
>>> b = 'connor'
>>> sum([1 for l in a if l in b])
4
EDIT
a,b = 'come','common'
def collision_count(a,b):
da = {l:a.count(l) for l in a}
db = {l:b.count(l) for l in b}
return sum(min(v,db[k]) for k,v in da.items() if k in db.keys())
print collision_count(a,b)
3
Are you now ok with that?