Question

我有一个包含如此多值的文件，如下所示

{'Name':'xyz','Date':'Thu Jun 26 13:14:17 +0000 2008'}
{'Name':'xyz','Date':'Thu Jun 19 13:14:17 +0000 2009'}
{'Name':'xyz','Date':'Thu Jun 26 13:15:17 +0000 2008'}

如何根据日期和时间对这些值进行排序？

Answer 1

如果文件每行有这一个，则需要转换为真实的dict，例如使用json.loads或ast.literal_eval，然后排序：

import json
import datetime

def parse_date(datestr):
    return datetime.datetime.strptime(datestr, '%a %b %m %H:%M:%S %z %Y')

with open(myfilename) as f:
    mydicts = map(json.loads, filter(str.strip, f))
    # This sorts on date value, but leaves them as original str
    # in dict, can convert ahead of time if you want, or not, as you please
    sorteddicts = sorted(mydicts, key=lambda d: parse_date(d['Date'])]

Answer 2

您可以使用dateutil.parser解析日期，并在key函数中添加正确的sort。
这有效 -

In [20]: from dateutil.parser import parse

In [21]: l = [{'Name':'xyz','Date':'Thu Jun 26 13:14:17 +0000 2008'},
{'Name':'xyz','Date':'Thu Jun 19 13:14:17 +0000 2009'},
{'Name':'xyz','Date':'Thu Jun 26 13:15:17 +0000 2008'}]

In [22]: sorted(l, key=lambda x: parse(x['Date']))
Out[22]:
[{'Date': 'Thu Jun 26 13:14:17 +0000 2008', 'Name': 'xyz'},
 {'Date': 'Thu Jun 26 13:15:17 +0000 2008', 'Name': 'xyz'},
 {'Date': 'Thu Jun 19 13:14:17 +0000 2009', 'Name': 'xyz'}]

Answer 3

您可以使用stdlib中的email包将日期格式解析为“自纪元以来的秒数”：

>>> from email.utils import parsedate_tz, mktime_tz
>>> mktime_tz(parsedate_tz('Thu Jun 26 13:14:17 +0000 2008'))
1214486057

很容易按dict字段对Date进行排序：

>>> sorted(dicts, key=lambda d: mktime_tz(parsedate_tz(d['Date'])))
[{'Date': 'Thu Jun 26 13:14:17 +0000 2008', 'Name': 'xyz'},
 {'Date': 'Thu Jun 26 13:15:17 +0000 2008', 'Name': 'xyz'},
 {'Date': 'Thu Jun 19 13:14:17 +0000 2009', 'Name': 'xyz'}]

要从文件加载json对象，可以使用code from @ShadowRanger's answer。

Python Dict（）根据datetime排序

3 个答案: