更快的datetime string to python datetime转换模块 ciso8601

https://github.com/closeio/ciso8601

ciso8601 converts ISO 8601 or RFC 3339 date time strings into Python datetime objects.

Since it's written as a C module, it is much faster than other Python libraries. Tested with Python 2.7, 3.4, 3.5, 3.6, 3.7.

当然，如果格式固定已知，那么从字符串里拆出指定位数的字符再转化为int也不算太慢

https://www.peterbe.com/plog/fastest-python-datetime-parser

def f1(datestr):
    return datetime.datetime.strptime(datestr, '%Y-%m-%dT%H:%M:%S.%fZ')


def f2(datestr):
    return ciso8601.parse_datetime(datestr)


def f3(datestr):
    return datetime.datetime(
        int(datestr[:4]),
        int(datestr[5:7]),
        int(datestr[8:10]),
        int(datestr[11:13]),
        int(datestr[14:16]),
        int(datestr[17:19]),
    )

• f1: baseline
• f2: 13 times faster
• f3: 6 times faster