Summing list of counters in python

Question

I am looking to sum a list of counters in python. For example to sum:

counter_list = [Counter({\"a\":1, \"b\":2}), Counter({\"b\":3, \"c\":4})]

Answer 1

This version was faster in my experience. This is upper bound by O(log(n)).

def sum_counters(counter_list):

    '''
    Recursive counter with a O(log(n)) Complexity
    '''

    if len(counter_list) > 10:

        counter_0 = sum_counters(counter_list[:int(len(counter_list)/2)])
        counter_1 = sum_counters(counter_list[int(len(counter_list)/2):])

        return sum([counter_0, counter_1], Counter())

    else:

        return sum(counter_list, Counter())

global_counter = sum_counters(counter_list)