Re: [R] Dealing with null values Aggregate function

From: Jannis <bt_jannis_at_yahoo.de>
Date: Tue, 17 May 2011 11:22:55 +0200

Andy,

have a look at ?mean. The na.omit argument set to TRUE should solve your problem. The use in aggregate would be something like:

aggregate(x = testDF, by = list(testDF$v3), FUN = function(x) mean(x,na.rm=TRUE))

HTH
Jannis

On 05/17/2011 04:27 AM, Andrew McFadden wrote:
> Hi R users
>
> I trying to some aggregate statistics on a very large dataset. The null
> values are causing a problem. I would like to calculate aggregate values
> for groups. I am just no sure how to deal with the "" I would ideally
> like them to ignored ie if there is only 1 value over several columns
> than that value would be the summary statistic.
>
> I have put the following example together to show my problem.
>
> testDF<- data.frame(v1 = c(1,3,5,7,8,3,5,NA,4,5,7,9),
> v2 = c(11,33,55,77,88,33,55,NA,44,55,77,99),
>
> v3=c("red","red","red","red","red","red","blue","blue","blue","blue","bl
> ue","blue"))
>
> aggregate(x = testDF, by = list(testDF$v3), FUN = "mean")
>
> For this example I would like to get a mean value for red (v1=4.5; v1=5)
> and blue (v1=49.5; v2=55)
>
> Thank you in advance.
>
> Andy
>
> Andrew McFadden MVS BVSc
> Incursion Investigator
> Investigation& Diagnostic Centres - Wallaceville Biosecurity New
> Zealand Ministry of Agriculture and Forestry
>
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> Investigation and Diagnostic Centre- Wallaceville Box 40742 Ward St
> Upper Hutt
>
>
>
>
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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Tue 17 May 2011 - 09:25:54 GMT

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