[R] sdate<-as.POSIXct(strptime(date,format="%m/%d/%Y %H:%M"))

[Prof Brian Ripley]

Please do read the posting guide and supply the information asked for.
There is nothing here I can reproduce:

Sys.setenv(TZ="EST5EDT")
date <- c("11/19/2006 00:00", "11/19/2006 00:10")
as.POSIXct(strptime(date,format="%m/%d/%Y %H:%M"))

gives

[1] "2006-11-19 00:00:00 EST" "2006-11-19 00:10:00 EST"

on both Mac OS X and Linux.

So what does sessionInfo() give on your system, and what timezone are you 
using?

On Wed, 31 Dec 2008, Graves, Gregory wrote:

> Newbie here~
>
> I've spent a ton of time on this, but have to admit I am stuck.  I've tried various combinations of strptime and the package CHRON, but still can't get there.
>
> My simple task is that I want to plot salinity (S1 or S2) on y-axis and time on x-axis, but I want to use a lay-understandable representation of time (not Julian).  If I use the following command, I can make a plot using "plot(S1~sdate)", where:
>
> sdate<-as.POSIXct(strptime(date,format="%m/%d/%Y %H:%M"))
>
> ... however, every 00:00 time winds up being an NA.  Here is an excerpt of the input data (this is a HUGE file):
>
> index                        Date       Julian         S1      S2
> 24985       11/19/2006 00:00 39040.01 20.40 22.11  (this line winds up being an NA)
> 24986       11/19/2006 01:00 39040.05 20.42 22.22
> 24987       11/19/2006 02:00 39040.09 20.60 22.29
> 24988       11/19/2006 03:00 39040.14 20.62 22.21
> 24989       11/19/2006 04:00 39040.18 20.75 22.39
>
> ... an excerpt of the variable "sdate" winds up looking like this:
>
> [35017] NA                        "2007-09-08 01:00:00 EDT"
> [35019] "2007-09-08 01:00:00 EDT" "2007-09-08 10:00:00 EDT"
> [35021] "2007-09-08 10:00:00 EDT" "2007-09-08 11:00:00 EDT"
> [35023] "2007-09-08 11:00:00 EDT" "2007-09-08 12:00:00 EDT"
> [35025] "2007-09-08 02:00:00 EDT" "2007-09-08 02:00:00 EDT"
> [35027] "2007-09-08 03:00:00 EDT" "2007-09-08 03:00:00 EDT"
> [35029] "2007-09-08 04:00:00 EDT" "2007-09-08 04:00:00 EDT"
> [35031] "2007-09-08 05:00:00 EDT" "2007-09-08 05:00:00 EDT"
> [35033] "2007-09-08 06:00:00 EDT" "2007-09-08 06:00:00 EDT"
> [35035] "2007-09-08 07:00:00 EDT" "2007-09-08 07:00:00 EDT"
> [35037] "2007-09-08 08:00:00 EDT" "2007-09-08 08:00:00 EDT"
> [35039] "2007-09-08 09:00:00 EDT" "2007-09-08 09:00:00 EDT"
> [35041] NA                        "2007-09-09 01:00:00 EDT"
> [35043] "2007-09-09 01:00:00 EDT" "2007-09-09 10:00:00 EDT"
> [35045] "2007-09-09 10:00:00 EDT" "2007-09-09 11:00:00 EDT"
> [35047] "2007-09-09 11:00:00 EDT" "2007-09-09 12:00:00 EDT"
> [35049] "2007-09-09 02:00:00 EDT" "2007-09-09 02:00:00 EDT"
> [35051] "2007-09-09 03:00:00 EDT" "2007-09-09 03:00:00 EDT"
> [35053] "2007-09-09 04:00:00 EDT" "2007-09-09 04:00:00 EDT"
> [35055] "2007-09-09 05:00:00 EDT" "2007-09-09 05:00:00 EDT"
> [35057] "2007-09-09 06:00:00 EDT" "2007-09-09 06:00:00 EDT"
> [35059] "2007-09-09 07:00:00 EDT" "2007-09-09 07:00:00 EDT"
> [35061] "2007-09-09 08:00:00 EDT" "2007-09-09 08:00:00 EDT"
> [35063] "2007-09-09 09:00:00 EDT" "2007-09-09 09:00:00 EDT"
>
>
> Gregory A. Graves
> Lead Scientist
> RECOVER Division
> Everglades Restoration Resource Area
> South Florida Water Management District
> Phones:  DESK: 561 / 681 - 2563 x3730
>             CELL:  561 / 719 - 8157
>
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

-- 
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