Convert dt to POSIXct class:


wtd$dt <- as.POSIXct(wtd$dt)
subset(wtd, format(dt, '%M') == 53)

On Mon, Jun 22, 2009 at 9:58 PM, Keith Jones <keithlj@keithljelp.com> wrote:

> Hi,
>
> I have a data frame with two columns: dt and tf.  The dt column is datetime
> and the tf column is a temperature.
>
>                               dt  tf
> 1 2009-06-20 00:53:00 73
> 2 2009-06-20 01:08:00 73
> 3 2009-06-20 01:44:00 72
> 4 2009-06-20 01:53:00 71
> 5 2009-06-20 02:07:00 72
> ...
>
> I need a subset of the rows where the minutes are 53.  The hour is
> immaterial.  I can not find a wildcard character to use to select the rows.
>
> as.character(wtd$dt) %in% "2009-06-21 ??:53:00" or as.character(wtd$dt)
> %in% "2009-06-21 **:53:00" does not work.
>
> What would you recommend?
>
> Thanks,
>
> Keith Jones, Ph.D.
> VTS Pumps
>
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>



-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

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