Question

我正在尝试使用python检查用户输入的字符串是否包含日期。

类似这样的东西。

user_input = ("Enter date")
if user_input==#type of date(yyyy-mm-dd):
    print(okay)
else:
    print("failed")

Answer 1

dateutil库是解析日期时最好的朋友：

>>> from dateutil.parser import *
>>> parse('2003-12-23')
datetime.datetime(2003, 12, 23, 0, 0)
>>> parse('2003-12-32')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "c:\srv\venv\dev\lib\site-packages\dateutil\parser\_parser.py", line 1356, in parse
    return DEFAULTPARSER.parse(timestr, **kwargs)
  File "c:\srv\venv\dev\lib\site-packages\dateutil\parser\_parser.py", line 653, in parse
    ret = self._build_naive(res, default)
  File "c:\srv\venv\dev\lib\site-packages\dateutil\parser\_parser.py", line 1227, in _build_naive
    naive = default.replace(**repl)
ValueError: day is out of range for month
>>>

如果您想更具限制性，即只接受YYYY-MM-DD格式的日期，然后先使用正则表达式检查可能是您的事：

def is_date(ds):
    if re.match(r'\d{4}-\d{2}-\d{2}', ds):
         return bool(parse(ds))
    return False

>>> is_date('2003-12-23')
True
>>> is_date('2003-12-32')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 3, in is_date
  File "c:\srv\venv\dev\lib\site-packages\dateutil\parser\_parser.py", line 1356, in parse
    return DEFAULTPARSER.parse(timestr, **kwargs)
  File "c:\srv\venv\dev\lib\site-packages\dateutil\parser\_parser.py", line 653, in parse
    ret = self._build_naive(res, default)
  File "c:\srv\venv\dev\lib\site-packages\dateutil\parser\_parser.py", line 1227, in _build_naive
    naive = default.replace(**repl)
ValueError: day is out of range for month

如果您不想成为相当的限制性对象，而是接受所有等格式的日期，则：

from dateutil.parser import isoparse
>>> isoparse('2003-12-23')
datetime.datetime(2003, 12, 23, 0, 0)
>>> isoparse('20031223')
datetime.datetime(2003, 12, 23, 0, 0)

Answer 2

这就是您想要的：

>>> import datetime
>>> def validate(date_text):
    try:
        datetime.datetime.strptime(date_text, '%Y-%m-%d')
    except ValueError:
        raise ValueError("Incorrect data format, should be YYYY-MM-DD")


>>> validate('2003-12-23')
>>> validate('2003-12-32')

Traceback (most recent call last):
  File "<pyshell#20>", line 1, in <module>
    validate('2003-12-32')
  File "<pyshell#18>", line 5, in validate
    raise ValueError("Incorrect data format, should be YYYY-MM-DD")
ValueError: Incorrect data format, should be YYYY-MM-DD

使用python检查输入字符串是否包含日期（特别是yy-mm-dd格式）

2 个答案: