You could loop over the list of reasonable formats,
using the first one that works (does not return NA):
f <- function (strings, formats) {
times <- strptime(strings, formats[1])
i <- 1
while ((i < length(formats)) && any(isBad <- is.na(times))) {
i <- i + 1
times[isBad] <- strptime(strings[isBad], formats[i])
}
times
}
E.g.,
> s <- c("2009-04-08 1:49:47 PM",
+ "2009-04-08 1:49 PM",
+ "2011-06-17 2:01:03 AM")
> fmts <- c("%Y-%m-%d %I:%M:%S %p", "%Y-%m-%d %I:%M %p")
> f(s, fmts)
[1] "2009-04-08 13:49:47" "2009-04-08 13:49:00" "2011-06-17 02:01:03"
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
> -----Original Message-----
> From: r-help-boun...@r-project.org
> [mailto:r-help-boun...@r-project.org] On Behalf Of cassie jones
> Sent: Friday, June 17, 2011 9:55 AM
> To: r-help@r-project.org
> Subject: [R] issue with strptime
>
> Hi everyone,
>
> I have bunch of date and time observations in the format
> %Y-%m-%d %I %M %S
> %p. I used strptime() to read this format. But the problem is
> some of the
> times are in the format of %I %M %p, so for those times,
> strptime is giving
> me NA values.
>
> For example,
>
> strptime(paste("2009-04-08","1:49:47 PM"),format="%Y-%m-%d
> %I:%M:%S %p")
>
> [1] "2009-04-08 13:49:47"
>
>
> But
>
> strptime(paste("2009-04-08","1:49 PM"),format="%Y-%m-%d %I:%M:%S %p")
>
> [1] NA
>
> Now I have approximately 10000 observations, so I can't go
> through all the
> observations individually in order to find which row in the
> array has this
> format.
>
> Can anyone suggest me how to handle this issue? Is there any
> way to convert
> %I %M %p format to %I %M %S %p?
>
> Thanks in advance for the help.
>
> Cassie
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
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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.
>
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and provide commented, minimal, self-contained, reproducible code.
