Python 如何在包含时间戳的词典列表中找到每天的第一个时间

发布于02月28日

我有一份这样的辞典 list :

data = [
    {"Zeit": datetime(2024, 2, 27, 8, 0), "km": 10},
    {"Zeit": datetime(2024, 2, 27, 13, 30), "km": 20},
    {"Zeit": datetime(2024, 2, 27, 17, 30), "km": 40},
    {"Zeit": datetime(2024, 2, 28, 9, 15), "km": 15},
    {"Zeit": datetime(2024, 2, 28, 14, 45), "km": 25}
]

现在我想找出每天的第一个时间，并指定Km=0.这应该会导致这样的结果:

data = [
    {"Zeit": datetime(2024, 2, 27, 8, 0), "km": 0},
    {"Zeit": datetime(2024, 2, 27, 13, 30), "km": 20},
    {"Zeit": datetime(2024, 2, 27, 17, 30), "km": 40},
    {"Zeit": datetime(2024, 2, 28, 9, 15), "km": 0},
    {"Zeit": datetime(2024, 2, 28, 14, 45), "km": 25}
]

我该怎么做？

到目前为止，我甚至没有找到一个很好的起点来处理这个问题.

推荐答案

try :

from datetime import datetime
from itertools import groupby

data = [
    {"Zeit": datetime(2024, 2, 27, 8, 0), "km": 10},
    {"Zeit": datetime(2024, 2, 27, 13, 30), "km": 20},
    {"Zeit": datetime(2024, 2, 27, 17, 30), "km": 40},
    {"Zeit": datetime(2024, 2, 28, 9, 15), "km": 15},
    {"Zeit": datetime(2024, 2, 28, 14, 45), "km": 25},
]

# sort if needed:
# data.sort(key=lambda d: d["Zeit"])

for _, g in groupby(data, lambda d: (d["Zeit"].year, d["Zeit"].month, d["Zeit"].day)):
    first = next(g)
    first["km"] = 0

print(data)

打印:

[
    {"Zeit": datetime.datetime(2024, 2, 27, 8, 0), "km": 0},
    {"Zeit": datetime.datetime(2024, 2, 27, 13, 30), "km": 20},
    {"Zeit": datetime.datetime(2024, 2, 27, 17, 30), "km": 40},
    {"Zeit": datetime.datetime(2024, 2, 28, 9, 15), "km": 0},
    {"Zeit": datetime.datetime(2024, 2, 28, 14, 45), "km": 25},
]