python - 使用正则表达式删除字符串末尾不可预测的日期格式

Question

我通过以下方式获取字符串，最后以随机模式显示日期。但它只会包含下划线、斜杠、数字或连字符。

TRAVEL_DELAY_01072015
TRAVEL_DELAY_01_07_2015
TRAVEL_DELAY_2015/01/04
TRAVEL_DELAY_2015-01-04

我只需要从上面的字符串中取出 TRAVEL_DELAY。我正在为此使用正则表达式，但不起作用:

m = re.match("^(.*)[_0-9\/.]+", abovestring)

Answer 1

如果您只想拆分日期:

s="""TRAVEL_DELAY_01072015
TRAVEL_DELAY_01_07_2015
TRAVEL_DELAY_2015/01/04
TRAVEL_DELAY_2015-01-04"""

for line in s.splitlines():
    date = line.split("_",2)[-1]

01072015
01_07_2015
2015/01/04
2015-01-04

或者str.replace，不需要正则表达式:

for line in s.splitlines():
    date = line.replace("TRAVEL_DELAY_","")
    print(date)

 01072015
 01_07_2015
 2015/01/04
 2015-01-04

如果您实际上是在尝试解析日期，您可以使用 dateutil 并修复字符串:

from dateutil import parser
for line in s.splitlines():
    date = line.replace("TRAVEL_DELAY_","")
    if any(ch in date for ch in ("/","-","_")):
        print(parser.parse(date.replace("_","-")))
    else:
        date = "{}-{}-{}".format(date[:2],date[2:4],date[4:])
        print(parser.parse(date))


2015-01-07 00:00:00
2015-01-07 00:00:00
2015-01-04 00:00:00
2015-01-04 00:00:00

如果数字只在日期中，而您实际上想要的是字符串而不是日期:

 s="""TRAVEL_DELAY_01072015
TRAVEL_DELAY_01_07_2015
TRAVEL_DELAY_2015/01/04
Travel_Delay_Data_2015/01/04
TRAVEL_DELAY_2015-01-04"""

for line in s.splitlines():
    ind = next(ind for ind, ele in enumerate(line) if ele.isdigit())
    s = line[:ind-1]
    print(s)

TRAVEL_DELAY
TRAVEL_DELAY
TRAVEL_DELAY
Travel_Delay_Data
TRAVEL_DELAY