Message-ID: <87ofcltg5p.fsf@jeeves.blindglobe.net>
Date: 2002-08-02T15:49:06Z
From: A.J. Rossini
Subject: extracting data from a dataframe
In-Reply-To: <20020802153146.GA3619@isis.visi.com>
>>>>> "tim" == Tim Wilson <wilson at 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 at u.washington.edu
FHCRC/SCHARP/HIV Vaccine Trials Net rossini at scharp.org
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