From: Chuck Cleland <ccleland_at_optonline.net>

Date: Thu 09 Feb 2006 - 01:48:51 EST

Date: Thu 09 Feb 2006 - 01:48:51 EST

Bernhard Baumgartner wrote:

> I have a dataframe with a column, say "x" consisting of values, each

*> value appearing different times, e.g.
**> x: 1,1,1,1,2,2,4,4,4,9,10,10,10,10,10 ...
**> and a vector, including e.g.:
**> y: 2,9,10,...
**> I need a subset of the dataframe: all rows where x is equal to one of
**> the values in y. Currently I use a loop for this, but because x and y
**> are large this is very slow.
**> Is there any idea how to solve this problem faster?
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mydata <- data.frame(X = sample(1:10, 10000, replace=TRUE),

Y = sample(c(2,9,10), 10000, replace=TRUE))

newdata <- mydata[mydata$X %in% unique(mydata$Y),]

?"%in%"

-- Chuck Cleland, Ph.D. NDRI, Inc. 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 452-1424 (M, W, F) fax: (917) 438-0894 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.htmlReceived on Thu Feb 09 03:36:02 2006

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