On Tue, 21 Dec 2004, Eva Goldwater wrote:
Well, at least that explains why stderr refers to files. But not why
stddev doesn't like to be invoked by by().
Someone suggested an alternate solution using split, but I'm the kind of
person that also wants to know why something that looks as it it ought to
work doesn't...
by() passes a data frame, and stdev does not accept dataframes, but a
`numeric vector or matrix'. (I thought I had seen several replies to that
effect.) Use tapply() instead.
Eva Goldwater email: goldwater@schoolph.umass.edu
Biostatistics Consulting Phone: (413) 545-2949
418 Arnold House Fax: (413) 545-1645
715 North Pleasant Street
University of Massachusetts
Amherst, MA 01003-9304
On Tue, 21 Dec 2004, Prof Brian Ripley wrote:
On Tue, 21 Dec 2004, Lucke, Joseph F wrote:
Eva
Under the UNIX operating system, stderr is the standard error file,
along with stdin and stdout. The history of S-PLUS involves UNIX.
Actually, `sterr' is part of the C language standard (section 7.13.1 in
the version I looked at), not UNIX, and S-PLUS is a C-based program using
C I/O. It is a _connection_ in S4, on which current versions of S-PLUS
are based.
Joe
-----Original Message-----
From: s-news-owner@lists.biostat.wustl.edu
[mailto:s-news-owner@lists.biostat.wustl.edu] On Behalf Of Eva Goldwater
Sent: Tuesday, December 21, 2004 12:28 PM
To: s-news@lists.biostat.wustl.edu
Subject: [S] BY with stdev?
Hello,
I tried to get standard deviations for subgroups of a numeric column,
defined by another column. I'm using the by function, but it doesn't
work with stdev. It's fine with mean or summarize, but not stdev or
stderr. Here is my test. (This is S-Plus 6.2 on Windows.)
x <- data.frame(cbind(x1=rep(1:2,5), x2=runif(10)))
by(x$x2,x$x1,mean)
by(x$x2,x$x1,stdev)
Problem in as.double: Cannot coerce mode list
to double: list(c(0.361767916940153, 0.132468292489....
Use traceback() to see the call stack
by(x$x2,x$x1,stderr)
Problem in FUN(...X.sub.i...., str..: Too many
arguments(1) in call to "FUN"; last 1 not matched
Use traceback() to see the call stack
What's the problem? Incidentally, ?stderr takes me to help for the
file() function...
Thanks for your insights. Eva
Eva Goldwater email:
goldwater@schoolph.umass.edu
Biostatistics Consulting Phone: (413) 545-2949
418 Arnold House Fax: (413) 545-1645
715 North Pleasant Street
University of Massachusetts
Amherst, MA 01003-9304
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Brian D. Ripley, ripley@stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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Brian D. Ripley, ripley@stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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