# [R] Is the aggregate function the best way to do this?

Mohamed Lajnef Mohamed.lajnef at inserm.fr
Wed Feb 17 10:29:18 CET 2010

Hi Bert,

apply(data,1,max) gives the max value for each row in the data

M

Bert Jacobs a écrit :
> Hi Mohamed,
> And what should I do if my fun function is not 'sum' but 'max'?
> Bert
> -----Original Message-----
> From: Mohamed Lajnef [mailto:Mohamed.lajnef at inserm.fr]
> Sent: 17 February 2010 10:02
> To: Bert Jacobs
> Cc: r-help at r-project.org
> Subject: Re: [R] Is the aggregate function the best way to do this?
>
> Hi Bret,
>
> Try to use rowSums function
>
> M
>
> Bert Jacobs a écrit :
>
>> Hi,
>>
>>
>>
>> I'm having a dataframe 'Subset1' with a number of factor variables and 160
>> numerical variables
>>
>> Now I want to make sums for all rows that have the same values for the
>> different factor variables, except for the factor variables:
>>
> VAR1,VAR2,VAR3
>
>> who may have the same values.
>>
>> With the formula given below this works great, but in a situation with
>>
> 15000
>
>> rows and 13 factor variables the calculation takes more than 2 minutes.
>>
>> So my question is: Does anyone knows if there exists a faster alternative?
>>
>
>
>>
>>
>> Subset1.AGG <-
>> as.data.frame(aggregate(Subset1[,(ncol(Subset1)-159):ncol(Subset1)],
>> list(VAR1 = Subset1\$VAR1,VAR2=Subset1\$VAR2,VAR3 = Subset1\$VAR3), FUN=sum)
>>
> )
>
>>
>>
>> Thank you very much for helping me out,
>>
>> Bert
>>
>>
>> 	[[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>>
> http://www.R-project.org/posting-guide.html
>
>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
>>
>
>
>

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