python - 计算在 python 中具有特定术语的子列表

Question

我是新手，我想编写一个函数来输出包含特定元素的子列表的计数。但是我的函数只输出所有子列表中该特定术语的总数。

我的功能:

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

我的输出:

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

期望的输出:

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

因为 'a' 存在于 3 个子列表中..

谁能帮我修改我的函数以获得所需的输出？？

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