From: Alberto Vieira Ferreira Monteiro <albmont_at_centroin.com.br>

Date: Sat 21 Oct 2006 - 15:29:19 GMT

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.html and provide commented, minimal, self-contained, reproducible code. Received on Sun Oct 22 04:10:43 2006

Date: Sat 21 Oct 2006 - 15:29:19 GMT

Larry White wrote:

*>
*

> Sorry - this must be obvious,

*>
*

Yes, it is :-)

> I want to be able to filter data in a dataframe before analyzing it.

*> For example, I'd like to plot(a,b) but only include values where b >
**> 1000.
**>
*

If a and b are vectors, then b > 1000 is another vector of logical
values.

You can use logical vectors to select pieces of other vectors, like this:

x <- c(1, 2, 3)

y <- c(TRUE, FALSE, FALSE)

x[y]

# returns only the first element, 1

So, this plot can be done this way:

filter <- (b > 1000) # filter is a logical vector
a1 <- a[filter]

b1 <- b[filter]

# Now, a1 and b1 are, resp, a and b filtered
plot(a1, b1)

Alberto Monteiro

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.html and provide commented, minimal, self-contained, reproducible code. Received on Sun Oct 22 04:10:43 2006

Archive maintained by Robert King, hosted by
the discipline of
statistics at the
University of Newcastle,
Australia.

Archive generated by hypermail 2.1.8, at Sat 21 Oct 2006 - 18:30:11 GMT.

*
Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help.
Please read the posting
guide before posting to the list.
*