获取每个月/年对的第一个条目

import datetime

def get_first_item_per_month_year(data):
    result = []
    prev_date = None
    for item in data:
        date = item['date']
        if prev_date is None or (date.month != prev_date.month or date.year != prev_date.year):
            result.append(item)
        prev_date = date
    return result

# 示例数据
data = [
    {'date': datetime.datetime(2022, 1, 5), 'value': 10},
    {'date': datetime.datetime(2022, 1, 15), 'value': 20},
    {'date': datetime.datetime(2022, 2, 8), 'value': 30},
    {'date': datetime.datetime(2022, 2, 20), 'value': 40},
    {'date': datetime.datetime(2022, 3, 3), 'value': 50},
    {'date': datetime.datetime(2022, 3, 12), 'value': 60},
]

result = get_first_item_per_month_year(data)
print(result)

[
    {'date': datetime.datetime(2022, 1, 5), 'value': 10},
    {'date': datetime.datetime(2022, 2, 8), 'value': 30},
    {'date': datetime.datetime(2022, 3, 3), 'value': 50}
]