[R] SQL like function?

[Gabor Grothendieck]

Others have already pointed out %in% but regarding your comment about
SQL, you can use SQL to manipulate R data frames using the sqldf package
which provides an interface to lower level RSQLite (and RMySQL in the future)
routines.  The following examples use SQLite underneath:

DF <- data.frame(observation = c(1,2,3,4,5))
ID <- data.frame(ID = c(1, 3, 4))

library(sqldf)
sqldf("select observation, observation in (select * from ID) `ID?` from DF")

# or

sqldf("select observation, observation in (1, 3, 4) `ID?` from DF")

See home page at:

http://sqldf.googlecode.com


On 9/7/07, Takatsugu Kobayashi <tkobayas at indiana.edu> wrote:
> Hi RUsers,
>
> I am wonder if I can search observations whose IDs matches any of the
> values in another vector, such as in MySQL. While I am learing MySQL for
> future database management, I appreciate if anyone could give me a hint.
>
> Suppose I have one 5*1 vector containing observation IDs and
> frequencies, and one 3*1 vector containing observation IDs.
>
> observation<-c(1,2,3,4,5)
> ID<-c(1,3,4)
>
> Then, I would like to program a code that returns a results showing
> matched observations like
>
> result: TRUE FALSE TRUE TRUE FALSE
>
> I am reading S programming, but I cannot find a way to do this.
>
> Thank you very much.
>
> Taka
>
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