[R] Get means of matrix

[Jim Lemon]

Hi Jesus,
While I do not have your data and cannot test this, the problem may be that
you are using two different names for the data frame. Is this more or less
what you want?

datos<-data.frame(x1=sample(20:40,40,TRUE),x2=sample(20:40,40,TRUE),
 x3=sample(20:40,40,TRUE),csvdata=rep(1:2,each=20))
sapply(datos[datos$csvdata==1,],mean,na.rm=TRUE)
sapply(datos[datos$csvdata==2,],mean,na.rm=TRUE)

Jim


On Wed, Nov 18, 2015 at 9:19 PM, Jesús Para Fernández <
j.para.fernandez at hotmail.com> wrote:

> Hi everyone
>
> I have a dataframe "data" wich is the result of join multiple csv (400
> rows and 600cols every csv). The "data" dataframe has n rows and m columns
> (200000 rows and 600 cols) , and I have add a new colum, "csvdata", in
> which I specify the number of csv at wich those data belong.
>
> So, the dataframe "data" looks like:
>
> x1    x2     x3    ....    xn    csvdata
> 21   23    32    ....    12    1
> 27   21    39    ....    14    1
> 24   22    30    ....    11    1
> ..............................................
> 21   24    32    ....   19     2
> 27   21    39    ....    14    2
> ..............................................
> 27   22     30    ....    11    n
>
>
>
> I want to store into a matrix the mean values of different substes of data
> of every csv, for example:
>
> region1,1 (rows 1:20,columns 1:20) for every "csvdata" value
> region 2,1 (rows 21:40,columns 1:20) para every "csvdata" value
> ....
>
> And so on for hole data.frame.
>
> I have tryed:
>
> area1<-tapply(as.matrix(data[1:20,1]),datos$csvdata,mean,na.rm=T)
> area2<-tapply(as.matrix(data[1:20,1]),datos$csvdata,mean,na.rm=T)
>
> But this error is the output I obtain:
>
> Error in tapply(data[1:30, ], datos$nueva, mean, na.rm = T) :
>   arguments must have same length
>
> I´m sure that it is not very complex to do it, but I have no idea of how
> to do it.
>
> Thanks for all.
>
>
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>
>
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