datetime_formatter

datetime_formatter provides a DSL (domain-specific language) for formatting datetimes inline to strings. datetime_formatter is also capable of translating the datetime by most intervals, including some that are not supported by timedelta like "business_day" (skip weekends and holidays).

For example (see Available Output Formats for full details)

Use datetime_formatter to format dates effectively, including translations and holiday/weekend management using easy-to-remember shortcuts instead of esoteric strftime shortcuts, i.e. having to memorize that %m is month, while %M" is minute. For example, use YMD to refer to a YYYYMMDD formatting of a date.

datetime_formatter is especially useful for ingestion of configuration files where complicated date logic either has to be handled outside of the file itself, making understanding logic harder, or by making all configuration actual Python code -- which again makes reading harder and interoperability with non-Python much harder or impossible. datetime_formatter allows all of this formatting to be done inline, making configuration files easier to comprehend.

Install

The latest stable version can always be installed or updated via pip:

$ pip install --update datetime_formatter

Documentation

The documentation is hosted on Read the Docs.

Quick Start

datetime_formatter is intended to be used in one of two ways. You can either use the provided DateTimeFormatter class which inherits from string.Formatter, but overrides .format to provide unique functionality.

from datetime_formatter import DateTimeFormatter

dtf = DateTimeFormatter("2005-03-01 09:30:00")
dtf.format("Format this way %ISODATETIME% or that way %YYYY%-%MM%-%DD% %HH%:%MM:%SS%")
dtf.format("Or use translaters to change the datetime: %YYYYMMDD-P1Y%")

Or use the provided convenience function dtformat (aliased to dtfmt as well):

from datetime import datetime
from datetime_formatter import dtfmt

dtfmt(20050301, "YYYYMMDD") == "20050301"  # True
dtfmt("2005-03-01", "MMDDYY") == "030105"  # True
dtfmt("2005-03-01 08:30:00", "HHMMSS") == "083000" # True

You can use the dtfmt shortcut, intended for use within f-strings, or you can instantiate a DateTimeFormatter object and use its .format method (or take advantage of the fact that __call__ forwards to .format)

dtf = DateTimeFormatter(datetime(2005, 3, 1))
dtf.format("%YYYYMMDD%") == "20050301"

You can also translate dates and/or times using inline translation syntax, e.g.:

dtfmt(20050301, "YMD-M1D") == "20050228"
dtfmt(20050301, "YMD-M1Y") == "20040301"
dtfmt("20050301 08:30:00", "DATETIME-P1H") == "2005-03-01 09:30:00"

You can also convert to a new timezone on the fly, but only if you your datetime object is not timezone-naive.

from dateutil import tz

utc = tz.gettz("UTC")
est = tz.gettz("EST")
dt = datetime(2005, 3, 1, 8, 30, 0, 0, est)
dtfmt(dt, "ISODT", output_tz=utc) == "2005-03-01T13:30:00+00:00"

The full list of supported output shortcuts and translations are provided below. You can also use the holidays module with translations to skip well-known holidays, much like you can skip weekends using the business_day translation size.

import holidays
dtfmt(20061229, "DATE-P2B", holidays=holidays.US()) == "2007-01-03"

Please see the documentation for additional examples and detailed information.

Available Output Formats

These shortcuts are used either as the fmtstr argument to dtfmt or within a string passed to DateTimeFormatter.format - in the latter case, the fields to be replaced must be surrounded by %, e.g. %YYYYMMDD%.

Available Translations

Translations are made up of three parts. The direction (M or P) determines whether to go forward/backward (plus/minus). The unit (see table below for unit-types) determines how far each step takes us foward or backward. Finally the size is a non-negative integer that tells us how far to move in the provided units.

You can string together any combination of these three translation parts, e.g.:

dtfmt(20050301, "YMD-M1B")      # 20050301 minus 2 business days (20050225)
dtfmt(20050301, "YMD-P1Y")      # 20050301 plus 1 year (20060301)
dtfmt(20050301, "DATETIME-P1H") # 20050301 00:00:00 plus 1 hour: (2005-03-01 01:00:00)

Beta Version

The latest development (beta) version can be installed directly from GitHub:

$ pip install --upgrade https://github.com/nadime/datetime_formatter/tarball/beta

All new features are always first pushed to beta branch, then released on master branch upon official version upgrades.

Contributions

Issues and pull requests are always welcome. Please see here for more information.

License

Code and documentation are available according to the MIT License (see LICENSE).