timehash
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abeusher
An algorithm for creating user configurable, variable-precision sliding windows of time. Useful for binning time values in large collections of data.
timehash
About
timehash is an algorithm (with multiple reference implementations) for calculating variable precision sliding windows of time. When performing aggregations and correlations on large-scale data sets, the ability to convert precise time values into 'malleable intervals' allows for many novel analytics.
Using sliding windows of time <http://stackoverflow.com/questions/19386576/sliding-window-over-time-data-structure-and-garbage-collection>__
is a common practice in data analysis but prior to the timehash
algorithm it was more of an art than a science.
.. image:: timehash-shaded-partial.png
Features
- convert epoch miliseconds into an interval of time, depicted by an ASCII character 'hash' (a 'timehash')
- timehash values are well suited to referencing time intervals in key-value stores (e.g. Hbase, Acculumo, Redis)
- The creation of a compound key of space and time (e.g. geohash_timehash) is a powerful primitive for understanding geotemporal patterns
Implementations
python timehash <https://github.com/abeusher/timehash/blob/master/timehash/__init__.py>__- a reference implementation in pure python
perl timehash <https://github.com/abeusher/timehash/blob/master/timehash.pl>__- a reference implementation in perl
java timehash <https://github.com/abeusher/timehash/blob/master/TimeHash.java>__- a reference implementation in java
javascript time-hash <https://github.com/disarticulate/time-hash>__- port of reference implements
golang timehash <https://github.com/abeusher/timehash/blob/master/timehash.go>__- a reference implementation in Go
Usage
Example of calculating a timehash value in python:
.. code:: python
import timehash
import time
rightnow = time.time()
rightnow60 = rightnow + 60.0
rightnow_hash = timehash.encode(rightnow, precision=10)
rightnow60_hash = timehash.encode(rightnow60, precision=10)
print 'timehash of right now: %s' % rightnow_hash
print 'timehash of now +60s: %s'% rightnow60_hash
% timehash of right now: ae0f0ba1fc
% timehash of now +60s: ae0f0baa1c
License
Modified BSD License <http://en.wikipedia.org/wiki/BSD_licenses#3-clause_license_.28.22Revised_BSD_License.22.2C_.22New_BSD_License.22.2C_or_.22Modified_BSD_License.22.29>__
Contact
- TimeHash Guru:
AbeUsher <http://www.linkedin.com/in/socialnetworkanalysis>__ - Python Packager:
Kevin Dwyer / @pheared <https://twitter.com/pheared>__ - Golang implementation:
Justin Shelton / @kwonstant <https://twitter.com/kwonstant>__ - Javascript implementation:
Eric Xanderson <https://github.com/disarticulate>__ - Rust implementation:
Kevin Dwyer / @pheared <https://github.com/dwyerk/timeharsh>_ - C implementation
Sam Mason <https://github.com/ukitake>_ - C# implementation
Sam Mason <https://github.com/ukitake>_
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