From felix at nfrac.org  Wed May 19 04:41:27 2010
From: felix at nfrac.org (Felix Andrews)
Date: Wed, 19 May 2010 12:41:27 +1000
Subject: [Rd] pretty.Date(): new "halfmonth" time step
Message-ID: <AANLkTikQNlbzH5crGWHOi84ItVu_p4KDl0Gch8KNekhd@mail.gmail.com>

Hi R-devel / R-core

In the new pretty() methods for Date and POSIXct
https://svn.r-project.org/R/trunk/src/library/grDevices/R/prettyDate.R
there is currently a "pretty" time step listed as "15 DSTdays"... but
this actually doesn't line up well with months.

Much better to implement directly what this is trying to do: i.e. to
have a "halfmonth" time step. This is just the union of two "monthly"
sequences, one on the 1st of each month and another on the 15th of
each month.

With this in place we have:

prettyDate(as.Date(c("2002-02-02", "2002-05-01")))
# [1] "2002-02-15" "2002-03-01" "2002-03-15" "2002-04-01" "2002-04-15"
"2002-05-01"

The proposed patch is attached.

Regards
-Felix


-- 
Felix Andrews / ???
Postdoctoral Fellow
Integrated Catchment Assessment and Management (iCAM) Centre
Fenner School of Environment and Society [Bldg 48a]
The Australian National University
Canberra ACT 0200 Australia
M: +61 410 400 963
T: + 61 2 6125 4670
E: felix.andrews at anu.edu.au
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http://www.neurofractal.org/felix/


[Rd] pretty.Date(): new "halfmonth" time step
Felix Andrews