Re: [R] mean of a column in a list of data frames

[Rui Barradas]

Hello,

Try instead the following.

aList<- numeric(3)
for(i in 1:3){
      aList[i] <- mean(ownersList[[i]]$grossIncome)
}
aList

Hope this helps,

Rui Barradas


Em 05-02-2017 12:01, Brandon Payne escreveu:

I have a list of data frames,

     ownersList <- list(exp2004owners,exp2005owners,
                    exp2006owners,exp2007owners,
                    exp2008owners,exp2009owners,
                    exp2010owners,exp2011owners,
                    exp2012owners,exp2013owners,
                    exp2014owners)

  I want to take the mean of the first column $grossIncome.
  I can access the first column with

lapply(ownersList, "[[", 1)                      ##works

But I can't take the mean of that.
mean(lapply(ownersList, "[[", 1))          ##not working

There must be a more idiomatic way to write this with map or apply.

ownersIncome<- c(mean(ownersList[[1]]$grossIncome),
                  mean(ownersList[[2]]$grossIncome),
                  mean(ownersList[[3]]$grossIncome),
                  mean(ownersList[[4]]$grossIncome),
                  mean(ownersList[[5]]$grossIncome),
                  mean(ownersList[[6]]$grossIncome),
                  mean(ownersList[[7]]$grossIncome),
                  mean(ownersList[[8]]$grossIncome),
                  mean(ownersList[[9]]$grossIncome),
                  mean(ownersList[[10]]$grossIncome),
                  mean(ownersList[[11]]$grossIncome))

I tried a for loop, which also didn't work.

aList<-
     for(i in 1:3){
     mean(ownersList[[i]]$grossIncome)
}
aList

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