[R] subset with multiple criteria

[Gabor Grothendieck]

Here are two solutions:

# 1
merge(subset.coor, E.coor)

# 2
# note that we changed the names of the data frames
# for this solution since dot is an operator in SQL
library(sqldf)
sqldf("select * from subset_coor natural join E_coor")


On Mon, Jun 23, 2008 at 12:32 PM,  <jgarcia at ija.csic.es> wrote:
> This should be theoretically very simple, but I dont get the elegant
> answer (without looping).
>
> I've got a long (thousands of rows) data frame:
>
>> E.coor[1:10,]
>     east   north       dat
> 1  582650 4248850 0.8316848
> 2  582750 4248850 0.7230272
> 3  582850 4248850 0.3250818
> 4  582950 4248850 0.6144006
> 5  583050 4248850 0.8706312
> 6  583150 4248850 0.2149651
> 7  583250 4248850 0.1659519
> 8  583350 4248850 0.2145174
> 9  583450 4248850 0.1615151
> 10 583550 4248850 0.9370766
>
> and need to extract those with the coordinates coinciding with those in a
> smaller data frame (about one hundred rows):
>
>> subset.coor
>     east   north
> 20 584550 4248850
> 21 584650 4248850
> 22 584750 4248850
> 23 584850 4248850
> 24 584950 4248850
> 25 585050 4248850
>
> i.e, I need the ~ one hundred E.coor rows that appear in subset.coor
>
> Could you help with this.
>
>
> Best regards,
> Javier
> ---------
>
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