The flexidate library supports date parsing and normalization using the FlexiDate class. It provides functionality to:

1. Cast dates according to the Anno Domini notation system (e.g., 399 BC, AD 417) as well as the Common Era notation system (e.g., 399 B.C.E, 417 CE)
2. Handle dates before AD 1 or 1 CE
3. Cast imprecise dates (c.1860, 18??, fl. 1534, etc)
4. Normalize dates to machine-readable data types
5. Create sortable date objects

Flexidate builds on the excellent dateutil.

For more information see this blog post.

First load a string into the parse function, which returns a FlexiDate object:

>>> from flexidate import parse
>>> fd = parse('Jan 1890')

Once you have your date in a FlexiDate object, you can get access to attributes:

>>> fd.year # u'1890'
'1890'
>>> fd.month # u'01'
'01'

Note how all fields are retained as strings, which prevents the loss of original input data.

The FlexiDate object exports to other formats (e.g., int or datetime):

>>> fd.as_float()
1890.0833333333333
>>> fd.as_datetime()
datetime.datetime(1890, 1, 1, 0, 0)

To cast years before AD 1:

To case dates before Christ (i.e., Anno Domini or Common Era):

>>> fd = parse('399 BC')
>>> fd
<class 'flexidate.FlexiDate'> -0399
>>> fd.year
'-0399'

Or after:

>>> fd = parse('AD 417')
>>> fd
<class 'flexidate.FlexiDate'> 0417

Including with Common Era notation:

>>> fd_ce = parse('399 BCE')
>>> fd_ce
<class 'flexidate.FlexiDate'> -0399
>>> fd_ad = parse('399 BC')
>>> fd_ce.year == fd_ad.year
True

>>> fd_ce = parse('417 CE')
>>> fd_ce
<class 'flexidate.FlexiDate'> 0417
>>> fd_ad = parse('AD 417')
>>> fd_ce.year == fd_ad.year
True

FlexiDate supports hour, minute, second, and microsecond:

>>> fd = parse('417-06-01 10')
<class 'flexidate.FlexiDate'> 2016-01-06 10
>>> fd.hour
'10'
>>> fd.minute
''

parse can capture various fuzzy date attributes. In FlexiDate this becomes available as the attribute qualifier:

>>> fd = parse('417?')
>>> fd
<class 'flexidate.FlexiDate'>  [b'UNPARSED: 417?']
>>> fd.qualifier
b'UNPARSED: 417?'

>>> fd = parse('c. 417')
>>> fd
<class 'flexidate.FlexiDate'> 0417 [Note 'circa' : c. 417]
>>> fd.qualifier
"Note 'circa' : c. 417"

>>> fd = parse('177?')
>>> fd
<class 'flexidate.FlexiDate'>  [b'UNPARSED: 177?']
>>> fd.qualifier
b'UNPARSED: 177?'

Comparison of dates:

>>> fd1 = parse('399 BC')
>>> fd2 = parse('AD 200')
>>> fd1.year < fd2.year
True
>>> fd1.year > fd2.year
False

To install required development dependencies: pip install -r requirements.txt.

Patches are welcome. Please include additional tests where relevant.

Tests can be found in flexidate/test_flexidate.py. Run using python flexidate/test_flexidate.py or, for a full coverage report, nosetests --no-skip --with-coverage.

To build locally: python -m build (you need build for it).

• Cast dates written in the Common Era notation system (e.g., 399 BCE, 417 CE)

MIT. See LICENSE.