Python: collections.Defaultdict() with tuples or lists as values

[sophryu99]

Declaring a defaultdict with default values as tuples or lists

d = collections.defaultdict(lambda: (0, 0))

Add values as a tuple to keys

• If key exists, increment the first element of the tuple by 1
• If not, add key, value to the dictionary

for i in range(len(s) -1 , -1, -1):
            if s[i] in d.keys():
                d[s[i]] = (d[s[i]][0] + 1, i)
            else:
                d[s[i]] = (1, i)

>>> s = "loveleetcode"
>>> defaultdict(<function Solution.firstUniqChar.<locals>.<lambda> at 0x7fbb1474c940>, {'e': (4, 3), 'd': (1, 10), 'o': (2, 1), 'c': (1, 8), 't': (1, 7), 'l': (2, 0), 'v': (1, 2)})

[sophryu99]

With set as default value

cnt = {}
        
        for log in logs:
            cnt.setdefault(log[0], set()).add(log[1])

Input:

[[0,5],[1,2],[0,2],[0,5],[1,3]]

Output:

{0: {2, 5}, 1: {2, 3}}

[sophryu99]

With list as default value and add list values

d = collections.defaultdict(lambda: list())
        
        for i, word in enumerate(s):
            d[word].append(i)