[R] splitting into multiple dataframes and then create a loop to work

[Dimitris Rizopoulos]

You can do this using function lmList() from package nlme, without 
having to split the data frames, e.g.,

library(nlme)

mlis <- lmList(yvar ~ .  - clvar | clvar, data = df)
mlis
summary(mlis)


I hope it helps.

Best,
Dimitris


On 8/29/2011 5:37 PM, Nilaya Sharma wrote:
> Dear All
>
> Sorry for this simple question, I could not solve it by spending days.
>
> My data looks like this:
>
> # data
> set.seed(1234)
> clvar<- c( rep(1, 10), rep(2, 10), rep(3, 10), rep(4, 10)) # I have 100
> level for this factor var;
> yvar<-  rnorm(40, 10,6);
> var1<- rnorm(40, 10,4); var2<- rnorm(40, 10,4); var3<- rnorm(40, 5, 2);
> var4<- rnorm(40, 10, 3); var5<- rnorm(40, 15, 8) # just example
> df<- data.frame(clvar, yvar, var1, var2, var3, var4, var5)
>
> # manual splitting
> df1<- subset(df, clvar == 1)
> df2<- subset(df, clvar == 2)
> df3<- subset(df, clvar == 3)
> df4<- subset(df, clvar == 4)
> df5<- subset(df, clvar == 5)
>
> # i tried to mechanize it
> *
>
> for(i in 1:5) {
>
>            df[i]<- subset(df, clvar == i)
>
> }
>
> I know it should not work as df[i] is single variable, do it did. But I
> could not find away to output multiple dataframes from this loop. My limited
> R knowledge, did not help at all !
>
> *
>
> # working on each of variable, just trying simple function
>   a<- 3:8
> out1<- lapply(1:5, function(ind){
>                     lm(df1$yvar ~ df1[, a[ind]])
>   })
> p1<- lapply(out1, function(m)summary(m)$coefficients[,4][2])
> p1<- do.call(rbind, p1)
>
>
> My ultimate objective is to apply this function to all the dataframes
> created (i.e. df1, df2, df3, df4, df5) and create five corresponding p-value
> vectors (p1, p2, p3, p4, p5). Then output would be a matrix of clvar and
> correponding p values
> clvar       var1   var2  var3  var4   var5
> 1
> 2
> 3
> 4
>
> Please help me !
>
> Thanks
>
> NIL
>
> 	[[alternative HTML version deleted]]
>
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>

-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
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