From: Petr Pikal <petr.pikal_at_precheza.cz>

Date: Thu 13 Jul 2006 - 16:00:28 EST

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 Received on Thu Jul 13 16:07:09 2006

Date: Thu 13 Jul 2006 - 16:00:28 EST

Hi

On 9 Jul 2006 at 20:01, Daryl Manning wrote:

To: r-help@stat.math.ethz.ch From: Daryl Manning <dwm@wakatara.com> Date sent: Sun, 9 Jul 2006 20:01:10 -0700 Subject: [R] How to get R to ignore certain values when analyzing a column in a data table ?

> Apologies if this is in (one of the many) manuals somewhere... Trying

*> to switch to R from other stats programs.
**>
**> Basically, I have a large data table I've dumped from a DB, some of
**> the values which are nulls '-' which I've converted to zeros. I've
**> read it in using read.table fine.
**>
**> I want R to ignore the zero values when graphing or doing various
**> other calculations.
**>
**> Is there a way to do this ?
**>
**> I did try to use NA but kept getting errors that x must be numeric.
*

What does str(your.data) says about your data? I presume it is factor.

datafr <- data.frame(a=rnorm(10), b=rnorm(10)) datafr[3,1]<-0

*> datafr$a
*

[1] -0.1645236 -0.2533617 0.0000000 0.5566632 -0.6887557 -
0.7074952 0.3645820 0.7685329 -0.1123462 0.8811077

*> mean(datafr$a)
*

[1] 0.06444035

*> datafr$a==0
*

** [1] FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
**

*> datafr$a[datafr$a==0]
*

[1] 0

*> datafr$a[datafr$a==0]<-NA
*

*> mean(datafr$a)
*

[1] NA

*> mean(datafr$a, na.rm=T)
*

[1] 0.07160039

*>
*

works OK.

**HTH
**

Petr

*>
*

> thanks in advance,

*> Daryl.
**>
**> ______________________________________________
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**> https://stat.ethz.ch/mailman/listinfo/r-help
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**> http://www.R-project.org/posting-guide.html
*

Petr Pikal

petr.pikal@precheza.cz

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 Received on Thu Jul 13 16:07:09 2006

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