[R] How to select a row from one dataframe that is "close" to a row in another dataframe

[Gabor Grothendieck]

Using the sqldf package you could do an SQL join with the indicated
condition in your where clause.  See the examples section of this
page: http://sqldf.googlecode.com

On Sat, Mar 20, 2010 at 10:20 AM, James Rome <jamesrome at gmail.com> wrote:
> I have two data frames of flight data,  but they have very different
> numbers of rows. They come from different sources, so the data are not
> identical.
>
>> names(oooi)
>  [1] "FltOrigDt"               "MkdCrrCd"
>  [3] "MkdFltNbr"               "DprtTrpnStnCd"
>  [5] "ArrTrpnStnCd"            "ActualOutLocalTimestamp"
>  [7] "ActualOffLocal"          "ActualOnLocal"
>  [9] "ActualInLocal"           "ArrivalGate"
> [11] "DepartureGate"           "Flight"
> [13] "OnDate"                  "MinutesIntoDay"
> [15] "OnHour"                  "pt"
>
>> names(runway)
>  [1] "OnDateTime"     "IATA"           "ICAO"           "Flight"
>  [5] "AircraftType"   "Tail"           "Arrived"        "STA"
>  [9] "Runway"         "From.To"        "Delay"          "OnDate"
> [13] "MinutesIntoDay" "pt"
>
> These sets have several hundred thousand rows.
>
> In both sets, pt is a POSIXct for the arrival time (from different
> sources). They are not identical, but surely should be within an hour of
> each other (hopefully a lot less), and the Flight fields must be the
> same. So
> (abs(runway$pt - oooi$pt) < 3600) & (runway$Flight == oooi$Flight)
> should pick out the corresponding rows in the two data sets (if there is
> a match).
>
> What I need to do is to take the Runway from runway and insert it into
> the oooi df for the correct flight.
>
> What is the best way to do this in R?
>
> Thanks,
> Jim Rome
>
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