count sublists that has a specific term in python

Question

I'm a newbie I want to write a function that outputs the count of sublists that contain a particular element. But my function just outputs the total count of that particular term in all the sublists.

My function:

def count(myList):
    tmp = []
    d = {}
    for item in myList: tmp += item
    for key in tmp: d[key] = d.get(key, 0) + 1
    return d

My output:

>>res = count_doc_frequencies([['a', 'b', 'a'], ['a', 'b', 'c'], ['a']])
>>res['a']
4
>>res['b']
2

Desired output:

>>res = count_doc_frequencies([['a', 'b', 'a'], ['a', 'b', 'c'], ['a']])
>>res['a']
3

As 'a' is present in 3 sublists..

can anyone help me modify my function to achieve the desired output ??

Answer 1

lst = [['a', 'b', 'a'], ['a', 'b', 'c'], ['a']]

def count(lst):
    # declare dictionary that we are going to return
    foo = {}
    # iterate sublist
    for sublist in lst:
        # make sublist into unique element list
        sublist = list(set(sublist))
        for element in sublist:
            # if element found in foo dic, increment
            if element in foo:
                foo[element] += 1
            # else, init with 1
            else:
                foo[element] = 1
    return foo

res = count(lst)
print res

Answer 2

You should change this statement

tmp += item

to

tmp += set(item)

This will eliminate the duplication count of elements in your sublists.