[R] Best way to do temporal joins in R?

[jim holtman]

check out the 'sqldf' package.  In
http://code.google.com/p/sqldf/#Example_4._Join there is an example of
a temporal join.  Maybe this will work for you.

On Fri, Apr 6, 2012 at 9:56 AM, Edith Mertz <mertz.em at gmail.com> wrote:
> Found the blunder, last line should have been:
>
> TideH$dt <- as.chron(paste(TideH$Date, TideH$Time), "%Y%m%d %H%M%S")
>
> After this I did:
>
> Fix <- read.csv("Fix times.csv")
> Fix[,"Station"] <- as.character(Fix[,"Station"])
> Fix[,"Date"] <- as.Date(Fix[,"Date"],format="%d/%m/%Y")
> Fix[,"Time"] <- as.character(Fix[,"Time"])
> Fix[,"Fix.Type"] <- as.character(Fix[,"Fix.Type"])
>
> Fix$DateTime<- as.chron(paste(Fix$Date, Fix$Time), "%Y%m%d %H%M%S")
>
> ds <- Fix$DateTime
> Fix$dt <- chron(sub(" .*", "", ds), gsub("[apm]+$|^.* ", "", ds)) +
>  (regexpr("pm", ds) > 0)/2
>
> Which gave an error list:
>
> Error in convert.dates(dates., format = format[[1]], origin. = origin.) :
>  format m/d/y may be incorrect
> In addition: Warning messages:
> 1: In unpaste(dates., sep = fmt$sep, fnames = fmt$periods, nfields = 3) :
>  17955 entries set to NA due to wrong number of fields
> 2: In convert.dates(dates., format = format[[1]], origin. = origin.) :
>  NAs introduced by coercion
> 3: In convert.dates(dates., format = format[[1]], origin. = origin.) :
>  NAs introduced by coercion
> 4: In convert.dates(dates., format = format[[1]], origin. = origin.) :
>  NAs introduced by coercion
>
> Now I'm lost 4sure, help?
>
>
> --
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-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.