Henrique, thanks for the response. As a new
user, I was unaware of with() and ave(), those are both very helpful.
However, I don't think your method is quite
right. I for all rows in each Key, I want the mean( IAC) where ProfA <= 0.
To simplify the problem, I have made a subset
dataframe that contains only the rows required
for the mean (data frame names changed from the original email) ...
FDP0D<-subset( FD, abs( FD$ProfA) < .01 & FD$IncA < 70, select=c(Key,IAC))
The first few rows of FDP0D look like this (note row names) ...
> FDP0D
Key IAC
11 B6-VB000.VB00045.3.12.3.0 0.889
12 B6-VB000.VB00045.3.12.3.0 0.889
13 B6-VB000.VB00045.3.12.3.0 0.890
14 B6-VB000.VB00045.3.12.3.0 0.890
15 B6-VB000.VB00045.3.12.3.0 0.891
16 B6-VB000.VB00045.3.12.3.0 0.892
17 B6-VB000.VB00045.3.12.3.0 0.893
83 B6-VB020.VB02045.3.12.3.0 0.852
84 B6-VB020.VB02045.3.12.3.0 0.852
85 B6-VB020.VB02045.3.12.3.0 0.852
(etc ... 630 rows)
Now I do the ave( )
> X<-with( FDP0D, ave( IAC, list( Key), mean))
And I get ...
function (x, ...)
UseMethod("mean")
<environment: namespace:base>
Error in unique.default(x) : unique() applies only to vectors
>
What's up? unique() seems to work OK on Key ...
> with( FDP0D, unique( Key))
[1] "B6-VB000.VB00045.3.12.3.0" "B6-VB020.VB02045.3.12.3.0"
[3] "B6-VB040.VB04045.3.12.3.0" "B6-VB060.VB06045.3.12.3.0"
[5] "B6-VB080.VB08045.3.12.3.0" "B6-VB100.VB10045.3.12.3.0"
[7] "BC6-VB000.VB00045.3.12.3.0" "BC6-VB020.VB02045.3.12.3.0"
[9] "BC6-VB040.VB04045.3.12.3.0" "BC6-VB060.VB06045.3.12.3.0"
(etc, 90 values which is correct)
Thanks,
Chip Barnaby
At 03:09 PM 4/30/2008, Henrique Dallazuanna wrote:
>If I understand your question:
>
> x$IAC0 <- with(x, ave(IAC, list(ProfA, Key), FUN = mean))
>
>On Wed, Apr 30, 2008 at 3:52 PM, Chip Barnaby
><<mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED]> wrote:
>Dear all --
>
>I have a data frame containing data related to
>heat gain through windows. The general form is ...
>
>Key ProfA IAC <many other numeric columns>
>AAA 0 .7
>AAA 10 .6
>AAA 0 .66
>AAA 20 .45
>(more AAA rows)
>(then AAB rows)
>
>'Key' identifies the physical configuration ...
>rows with a given Key contain data for same window under various conditions.
>
>I want to add a column IAC0 containing, for each
>Key, the mean IAC of all rows with ProfA == 0.
>
>The general approach I think I need is
>approximately (the following is not known to run) --
>
>1) XS<-subset( X, ProfA < .01) to get the ProfA
>== 0 rows. This could be done implicitly as part of step 2, I suppose.
>
>2) X0<-aggregate( XS[,"IAC"], by=list( Key=XS$Key), mean)
>
>3) XF<-merge( X, X0, by="Key")
>
>4) Change new col name to "IAC0" (see Question 2).
>
>Question 1: Is this a reasonable way to solve my problem?
>
>Question 2: The aggregate() result has 2
>columns: "Key" and "x". Can the name of the
>mean column be specified (short of renaming
>after the fact)? All the aggregate() examples
>(e.g. in help()) elegantly produce the "right
>result" with nicely named columns etc. I can't
>seem to make things work so smoothly.
>
>Thanks!
>
>Chip Barnaby
>
>
>
>
>
>
>
>
>
>---------------------------------------------------------
>Chip
>Barnaby
><mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED]
>Vice President of Research
>Wrightsoft Corp. 781-862-8719 x118 voice
>131 Hartwell Ave 781-861-2058 fax
>Lexington, MA 02421 <http://www.wrightsoft.com>www.wrightsoft.com
>
>______________________________________________
><mailto:R-help@r-project.org>R-help@r-project.org mailing list
><https://stat.ethz.ch/mailman/listinfo/r-help>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
><http://www.R-project.org/posting-guide.html>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.
>
>
>
>
>--
>Henrique Dallazuanna
>Curitiba-Paraná-Brasil
>25° 25' 40" S 49° 16' 22" O
---------------------------------------------------------
Chip Barnaby [EMAIL PROTECTED]
Vice President of Research
Wrightsoft Corp. 781-862-8719 x118 voice
131 Hartwell Ave 781-861-2058 fax
Lexington, MA 02421 www.wrightsoft.com
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