Tuesday, February 28, 2006

Re: st: timestamps and time

Brad De Groot wrote:

Would someone please direct me to descriptions of how to handle timestamps and times? I'm trying to use transaction timestamps from a relational database to display circadian patterns for system utilization through different interfaces and form factors. I htought it would be straightforward, but I have found the right sections of documentation or statalist archives.


-egen- has some time commands via the -egenmore- package (available from SSC). Kit Baum just posted that he's updated a couple of his contributions to the package in a couple of the commands that he contributed to it.

There's also a, uh, timely article by Nick Cox on the topic in the current issue of _The Stata Journal_. The electronic version of the issue's just come out this morning.

If you retrieve the timestamps in ISO 8601 format, then the data will sort correctly naturally as a string, and you can use either -split-, parsing on the "T", or -substr()- to get time alone for circadian analysis. You can use one of the commands mentioned in the article to convert to numeric--fraction of the day, seconds from midnight, etc., although it's not difficult to do the conversion from scratch.

Joseph Coveney

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