Dataframe calculation, anchor cell value to formula - r

Question

I would like to do some calculations with the following dataframe. There are some values in specific cells of a column, and I would like to have them replicated based on a second column value, and store these in a new, third column:
x <- c ("1", "2","3", "4")
z <- (rep(x,5))
batch <- sort(z)
NDF <- rnorm(20, 10, 1); NDF <- signif (NDF, digits =3)
Fibre_analysis <- data.frame(batch, NDF)
Fibre_analysis$NDF[[1]] <- 10
Fibre_analysis$NDF[[6]] <- 100
Fibre_analysis$NDF[[11]] <- 1000
Fibre_analysis$NDF[[16]] <- 10000
This is the table that I would like:
batch NDF NEW_column
1 1 10.00 10
2 1 10.80 10
3 1 9.44 10
4 1 10.30 10
5 1 11.60 10
6 2 100.00 100
7 2 8.26 100
8 2 9.15 100
9 2 9.40 100
10 2 8.53 100
11 3 1000.00 1000
12 3 9.41 1000
13 3 9.20 1000
14 3 10.30 1000
15 3 9.32 1000
16 4 10000.00 10000
17 4 11.20 10000
18 4 7.33 10000
19 4 9.34 10000
20 4 11.00 10000
I would like this to create a new column in the dataframe, with absolute cell values from $NDFthat have to change for each value of $batch.
Because I need to use this process more than once I created the following function:
batch_Function <- function (x,y){
ifelse (x =="1", y[[1]],
ifelse (x =="2", y[[6]],
ifelse (x =="3", y[[11]],
y[[16]] )))
print (y)
}
when I call the function:
Fibre_analysis$NEW_column <- batch_Function ( Fibre_analysis$batch , Fibre_analysis$NDF )
I expect $NEW_column to look like this:
x <- c(10,100,1000,10000)
NEW_column <- rep(x, each=5)
whereas instead it is the exact same copy of the $NDF.

Answer 1

The only necessary change is to drop print(y) as it is not allowing to return the actual result:
batch_Function <- function (x, y) {
ifelse (x =="1", y[[1]],
ifelse (x =="2", y[[6]],
ifelse (x =="3", y[[11]],
y[[16]] )))
}
batch_Function (Fibre_analysis$batch , Fibre_analysis$NDF )
# [1] 10 10 10 10 10 100 100 100 100 100 1000 1000 1000 1000
# [15] 1000 10000 10000 10000 10000 10000
In case you still want print(y), you may put it at the beginning of batch_Function.