This is the README of my python package snaptime. The github repo is here. I wanted to view the html markdown generates, so I put it here..


The snaptime package is about transforming timestamps in a simple manner.

It is inspired by splunks relative time modifiers, see docs here.

Motivating example:

Say Harry wants to send a letter and there is mailbox right to his door, which is cleared every day at 16:00h. The post delivers letters the next day at 11:00h. So given a datetime t - at which Harry throws the letter into the mailbox - when does the letter get delivered?

One straightforward implementation would be:

  1. check whether t is before or after 16:00h
  2. truncate hours, minutes and seconds
  3. add 1 or 2 days (according step 1) plus 11h

This would take some lines of code, but with snaptime the solution would be a one-liner:

from snaptime import snap
snap(t, "+8h@d+1d+11h")

In plain words this

  1. adds 8 hours to t (+8h)
  2. snaps to the beginning of the day (@d)
  3. adds one day and 11h (+1d+11h)

Two types of transformations

There are two types of transformations that can be chained freely in the snap function.

Snap Transformation

A snap transformation is written as @<timeunit>, which truncates to the given time unit. I.e. @h applied to a timestamp sets minutes, seconds and microseconds to zero. Snapping to seconds, minutes, days, months, years work the same way. Further it is also possible to snap to weeks (@w), and even to specific week days (@w0, @w1, …, @w6 for Sunday, Monday, …, Saturday).

Delta Transformation

A delta transformation (the name is kind of an overstatement..) works analogously to the datetime.timedelta object from the standard library. A signed number ([+-]\d+) and a time unit indicate the change on the given timestamp.

Time Units

There are several strings for each time unit that indicate that same time unit. Here is the full table:

Unit Equal notations
seconds s, sec, secs, second, seconds
minutes m, min, minute, minutes
hours h, hr, hrs, hour, hours
days d, day, days
weeks w, week, weeks
months mon, month, months
years y, yr, yrs, year, years

For a given datetime t i.e. this assertion holds true

assert snap(t, "-3hours@day+2weeks@month") == snap(t, "-3hrs@d+2w@mon")


>>> from datetime import datetime
>>> from snaptime import snap

>>> dt = datetime(2016, 7, 30, 15, 23, 59)
>>> snap(dt, "@d")
datetime(2016, 7, 30, 0, 0)

>>> snap(dt, "-3d@d")
datetime(2016, 7, 27, 0, 0)

>>> # some more here


Running unit test

git clone
cd snaptime
mkvirtualenv --python=/usr/bin/python2 snaptime
pip install -r requirements.pip

Please feel free to send comments and/or pull requests.