[R] Problem with plot() and POSIXt dates

[Prof Brian Ripley]

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On Fri, 5 Jan 2007, COMTE Guillaume wrote:

>
>
> Hy all,
>
>
>
> I'm plotting graphs using plot() function, they are on X axes POSIX dates:
>
> "POSIXt"   "oldClass" "POSIXct"  "POSIXlt"
>
> I can't figure out why sometimes it prints the month and days and sometimes it prints the unix timestamp.
>
> It appens usually when the xlim is short like only some days.
>
> xlim is settled as a POSIXt like this
>
> "2006-12-30 17:25:44 CET" "2007-01-02 03:16:51 CET"
>
> On the graph it prints : 1167500000 and 1167700000 instead of dates.
>
> And the result gives a x axes in unix timestamps as if the plot function didn't recognize that it is a timestamp but just an integer.
>
> What am i missing, since R sees itself that it is time stamps and not integer when xlim is enougth large, how do i tell the plot function to see these numbers as POSIXt?
>
> I put an attachement, inside there is an example that demonstrate what i experience (hope it won't be deleted, it is a tar.gz archive made using debian under
>
> R version 2.1.0, 2005-04-18, i386-pc-linux-gnu
>
> attached base packages:
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> [1] "methods"   "stats"     "graphics"  "grDevices" "utils"     "datasets"
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> [7] "base").
>
>
>
> thks.
>
> COMTE Guillaume
>
> Ingénieur Projet
>
> Alliance Technologies
>
> Projet Philharmonie
>
> 24 rue Martre
>
> 92110 Clichy
>
> Tel : 01 40 87 48 06
>
> Fax : 01 40 87 48 14
>
>
>
>

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595