Append to dataframe through for loop and function - r

Question

When I run a code with save as csv at the end everything runs correctly. It means I filter my dataset by country do some continuations and save it as a country file.
When I try to rbind my datasets I receive nothing. I try different solutions which I found but nothing is working. Clearly I do not understand why I can not rbind.
The code:
library(dplyr)
library(readxl)
setwd("Z:/Reporting_Private/Tableau")
dataupl <- read_excel("Analysis Map_Tableau - Ready.xlsm", sheet = "Data")
df = dataupl
#select right columns
df = df[,1:6]
colnames(df)=c("Office", "Employee","Territiry","Sales","Leads","Act")
#change n/a to zero
df[is.na(df)]=0
countries = df %>% select(Office) %>% distinct()
countries = as.data.frame(countries)
engine <- function(input){
df = df %>% filter(Office==input)
SCALESALES = scale(df$Sales)
SCALELEADS= scale(df$Leads)
SCALEACT= scale(df$Act)
df = df %>% mutate(SCALESALES = SCALESALES, SCALELEADS = SCALELEADS, SCALEACT = SCALEACT)
df$SLegend = ave(df$Sales, df$SalesLegend, FUN = min)
df$SLegend = ifelse(df$SLegend>0, df$SLegend,0)
df$LLegend = ave(df$Leads, df$LeadsLegend, FUN = min)
df$ALegend = ave(df$Act, df$ActLegend, FUN = min)
#write.csv(final, file = paste0(input,".csv"))
dftotal = data.frame()
dftotal = rbind(dftotal,df)
}
for (i in 1:nrow(countries)){
input = countries[i,]
engine(input)
}

Answer 1

It seems that you can split your dataframe L <- split(df, df$Office) and then lapply(L, ...) Instead of write.csv(...) you have to return the dataframe: return(df) in your function.
So, something like this:
engine <- function(dfi) {
SCALESALES = scale(dfi$Sales)
SCALELEADS = scale(dfi$Leads)
SCALEACT = scale(dfi$Act)
dfi = dfi %>% mutate(SCALESALES = SCALESALES, SCALELEADS = SCALELEADS, SCALEACT = SCALEACT)
dfi$SLegend = ave(dfi$Sales, dfi$SalesLegend, FUN = min)
dfi$SLegend = ifelse(dfi$SLegend>0, dfi$SLegend, 0)
dfi$LLegend = ave(dfi$Leads, dfi$LeadsLegend, FUN = min)
dfi$ALegend = ave(dfi$Act, dfi$ActLegend, FUN = min)
return(dfi)
}
L <- split(df, df$Office)
Lnew <- lapply(L, engine)
dftotal <- Lnew[[1]]
for (i in 2:length(Lnew)) dftotal <- rbind(dftotal, Lnew[[i]])