[R] Replacing NA values in one column of a data.frame

John Kane jrkrideau at yahoo.ca
Tue Aug 18 18:09:14 CEST 2009

Clearly the poor user needs to export something to one of those archaic stats systems like SAS or SPSS :)

--- On Tue, 8/18/09, Bert Gunter <gunter.berton at gene.com> wrote:

> From: Bert Gunter <gunter.berton at gene.com>
> Subject: RE: [R] Replacing NA values in one column of a data.frame
> To: "'Steve Lianoglou'" <mailinglist.honeypot at gmail.com>, "'John Kane'" <jrkrideau at yahoo.ca>
> Cc: r-help at r-project.org, "'Steve Murray'" <smurray444 at hotmail.com>
> Received: Tuesday, August 18, 2009, 11:27 AM
> -----Original Message-----
> From: r-help-bounces at r-project.org
> [mailto:r-help-bounces at r-project.org]
> On
> Behalf Of Steve Lianoglou
> Sent: Tuesday, August 18, 2009 7:25 AM
> To: John Kane
> Cc: r-help at r-project.org;
> Steve Murray
> Subject: Re: [R] Replacing NA values in one column of a
> data.frame
> ...** But do NOT do this.***  Unless you are using R
> to prepare your data
> for some other statistical analysis system (most unwise),
> there is **never**
> any reason in R to replace NA's with nonsense numerical
> codes -- and a great
> many reasons NOT to do this, to whit:
> 1) NA's are a special value in R (actually many, of
> different types) with
> extensive built-in capabilities to handle them properly,
> deal with them
> (often automatically) in fitting functions etc. Recoding to
> a nonsense
> numeric defeats all this careful machinery.
> 2) You are just begging for trouble by using nonsense
> numerics: if you
> forget your coding or someone else uses your data who's not
> aware of it,
> voilá ! -- you have just guaranteed that data analyses
> will be partial or
> complete garbage.
> Finally -- a request to well-meaning helpeRs: Just because
> you CAN do
> something in R statistically or programmatically does not
> mean you should.
> When someone requests something that you believe is the
> wrong thing to do, I
> think it within the bounds of both R etiquette and
> professional practice to
> tell them NOT to do it and explain why not. Of course,
> sometimes such
> admonitions are themselves ill-advised (as this may be),
> but an open,
> courteous, professional exchange on the issue will itself
> be informative to
> useRs.
> Cheers to all,
> Bert
> Bert Gunter
> Genentech Nonclinical Biostatisics 

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