itertools.groupby方法进行分组

import itertools
a = [
    {"a": 1, "b": 2},
    {"a": 2, "b": 4},
    {"a": 1, "b": 8},
    {"a": 3, "b": 5},
    {"a": 1, "b": 1},
]
a.sort(key=lambda _: _.get("a"))
print(a)
gb = itertools.groupby(a, lambda i: i.get("a"))
for i in gb:
    print(i)    # 元组
    for v in i[1]:
        print(v)

[{‘a‘: 1, ‘b‘: 2}, {‘a‘: 1, ‘b‘: 8}, {‘a‘: 1, ‘b‘: 1}, {‘a‘: 2, ‘b‘: 4}, {‘a‘: 3, ‘b‘: 5}]
(1, <itertools._grouper object at 0x000001F3184EB250>)
{‘a‘: 1, ‘b‘: 2}
{‘a‘: 1, ‘b‘: 8}
{‘a‘: 1, ‘b‘: 1}
(2, <itertools._grouper object at 0x000001F3184EB220>)
{‘a‘: 2, ‘b‘: 4}
(3, <itertools._grouper object at 0x000001F3184EB250>)
{‘a‘: 3, ‘b‘: 5}