From: A.J. Rossini (rossini@blindglobe.net)
Date: Sat 03 Aug 2002 - 01:49:06 EST
Message-id: <87ofcltg5p.fsf@jeeves.blindglobe.net>
>>>>> "tim" == Tim Wilson <wilson@visi.com> writes:
tim> Hi everyone,
tim> Here's a question about extracting data from a dataframe:
tim> Let's say I've got a dataframe with two vectors, TEST and GENDER. GENDER
tim> contains a 1 for males and 2 for females. I want to separate the results
tim> of TEST by GENDER so I can compare their means.
tim> What's the most efficient way to do this with R?
something like:
lapply(split(df$TEST,df$GENDER),mean)
?
(where "df" is the data.frame).
-- A.J. Rossini Rsrch. Asst. Prof. of Biostatistics U. of Washington Biostatistics rossini@u.washington.edu FHCRC/SCHARP/HIV Vaccine Trials Net rossini@scharp.org -------------- http://software.biostat.washington.edu/ ---------------- FHCRC: M: 206-667-7025 (fax=4812)|Voicemail is pretty sketchy/use Email UW: Th: 206-543-1044 (fax=3286)|Change last 4 digits of phone to FAX (my tuesday/wednesday/friday locations are completely unpredictable.)-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
This archive was generated by hypermail 2.1.3 : Tue 01 Jun 2004 - 09:31:04 EST