用Python解析时间戳 [英] Parsing Timestamp in Python

问题描述

我有一个应用程序，需要解析四种不同格式的时间戳。

I have an application in which I need to parse timestamps of four different formats.

HH:MM:SS
HH:MM:SS.mm
MM:SS
MM:SS.mm

如何编写将这些格式中的任何一种解析为 timedelta 对象的函数？

How can I write a function to parse any of these formats into a timedelta object?

I当我看到：时，尝试一个接一个地循环遍历字符和 break ，但是我的代码很混乱，所以我宁愿这里没有它作为基准。

I have tried iterating through the characters one by one and breaking when I see the :, but my code is a mess, so I would rather not have it here as a baseline.

推荐答案

这是使用 datetime.datetime.strptime（）：

如果您不提前知道哪个格式，然后输入，您可以尝试将所有输入换成 try / catch 块。

If you don't know ahead of time which format your input will be in, you can try all of them wrapped in a try/catch block.

strptime（）返回 datetime 对象，因此调用 .time（）函数仅获取时间部分。请参阅此帖子

strptime() returns a datetime object, so call the .time() function to get only the time part. See this post for more details.

import datetime

def parse_timestamp(ts):
    formats = [
        "%H:%M:%S", #HH:MM:SS
        "%H:%M:%S.%f", #HH:MM:SS.mm
        "%M:%S", #MM:SS
        "%M:%S.%f" #MM:SS.mm
    ]
    for f in formats:
        try:
            return datetime.datetime.strptime(ts, f).time()
        except ValueError:
            pass
    return None

示例：

timestamps = [
    "12:34:56",
    "12:34:56.78",
    "34:56",
    "34:56.78"
]
for ts in timestamps:
    print parse_timestamp(ts)

输出：

12:34:56
12:34:56.780000
00:34:56
00:34:56.780000

或者如果您知道特定格式，则可以直接使用 datetime.datetime.strptime（ts，f）.time（）。

Or if you know the specific format, you can use datetime.datetime.strptime(ts, f).time() directly.

更新1

如果要转换为 timedelta s，您可以使用 parse_timestamp（）和 timedelta 构造函数：

If you want to convert to timedeltas, you can do so using the output of parse_timestamp() and the timedelta constructor:

def time_to_timedelta(t):
    td = datetime.timedelta(
        seconds=t.second,
        microseconds=t.microsecond,
        minutes=t.minute,
        hours=t.hour
    )
    return td

这是与相关的帖子可能对您也有用。

Here is a related post that you may also find useful.

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