Use of paste/get in a loop-r

Question

My question is so trivial, I want to paste a vector in a loop like this

 Mysheetlandscap <- excel_sheets("C:/FAPSEP_Eucalyptus/FAPSEP/AHMED_GDAY/CloneParnew5_forCALIB2.xlsx")

for(j in 1:length(Mysheetlandscap)){

  ClonePar <- read_excel("C:/FAPSEP_Eucalyptus/FAPSEP/AHMED_GDAY/CloneParnew5_forCALIB2.xlsx", sheet = Mysheetlandscap[j])

  x <- ClonePar$,j,[!is.na(ClonePar$MIN_CL)]  #should return the vector ClonePar$j
  }

So I tried

get(paste0("ClonePar$",j))

Error in get(paste0("ClonePar$", j)) : object 'Cal_OCT_18_GLM$C041H' not found

What I'm missing?

I don't recognize your syntax with $,j, When looping you typically need to fill an empty list x <- list() and then have the looping index specified when you fill it with a loop ClonePar[j] <- read_excel("C:/FAPSEP_Eucalyptus/FAPSEP/AHMED_GDAY/CloneParnew5_forCALIB2.xlsx", sheet = Mysheetlandscap[j]) Also is x outside of your loop, it isn't clear since you don't have a terminal } — EJJ
– EJJ, Commented Oct 16, 2018 at 14:49
x is inside the loop and I need to assign the vector: ClonePar$,j,[!is.na(ClonePar$MIN_CL)] to x inside the loop — Ahmed Attia
– Ahmed Attia, Commented Oct 16, 2018 at 14:52
@AhmedAttia Yes, and do like EJJ says. Create ClonePar <- list() outside the loop. Then, inside the loop use j to assign values: ClonePar[[j]] <- whatever. — Rui Barradas
– Rui Barradas, Commented Oct 16, 2018 at 14:59

EJJ · Accepted Answer · 2018-10-16 15:32:24Z

1

note: I used seq_along instead of 1:length() so that you don't get any funky output if you have an empty data frame

If you want to use a for loop:

ClonePar <- list() #create empty list

for(j in seq_along(Mysheetlandscap)){

  ClonePar[j] <- read_excel("C:/FAPSEP_Eucalyptus/FAPSEP/AHMED_GDAY/CloneParnew5_forCALIB2.xlsx", sheet = Mysheetlandscap[j])

}

ClonePar[[1]] #look the first element (a data frame) in your newly filled list

If you want to use the apply family (based on Vladimir's answer):

ClonePar <- lapply(seq_along(Mysheetlandscap),
                   function(j) read_excel("C:/FAPSEP_Eucalyptus/FAPSEP/AHMED_GDAY/CloneParnew5_forCALIB2.xlsx", sheet = j))

in the case of using lapply you don't have to create an empty list before running the vectorized operation.

answered Oct 16, 2018 at 15:32

EJJ

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Vladimir Volokhonsky · Accepted Answer · 2018-10-16 15:00:51Z

0

It's hard to understand... But maybe it is what you want:

ClonePar <- lapply(1:length(Mysheetlandscap), function(j)
read_excel("C:/FAPSEP_Eucalyptus/FAPSEP/AHMED_GDAY/CloneParnew5_forCALIB2.xlsx", sheet = j))

j<-10
x <- ClonePar[[10]]

answered Oct 16, 2018 at 15:00

Vladimir Volokhonsky

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