from collections import defaultdict
s = [('class',1),('rose', 2), ('bob', 3), ('bob', 4), ('rose', 1)]
d = defaultdict(list)
for k,v in s:
d[k].append(v)
print(d)
dic = defaultdict(set)
for k, v in s:
dic[k].add(v)
print(dic)
# 输出结果
defaultdict(<class 'list'>, {'class': [1], 'rose': [2, 1], 'bob': [3, 4]})
defaultdict(<class 'set'>, {'class': {1}, 'rose': {1, 2}, 'bob': {3, 4}})