Write error in r using trycatch - r

Question

I have used trycatch so that if error happened during execution of r code it will not break.
I wanted to write error in one of the file , but not sure how it can be done.
Below is code used
library(forecast)
library(data.table)
library(RODBC)
forecast_data <- data.frame(Project_ID=character(),
Period_End=character(),
Point_Forecast=character(),
Lower_Limit_95=character(),
Upper_Limit_95=character(),
stringsAsFactors=FALSE)
Data <- read.csv("Data.csv", header=TRUE,na.strings=c("NULL",""))[ ,c('Project_ID', 'Period_End_Date', 'Overall_Backlog_Processing_Efficiency_Incident')]
result = tryCatch({
if (nrow(Data) >= 1)
{
backlog <- as.vector(Data$Overall_Backlog_Processing_Efficiency_Incident)
i <- 1
datalist = list()
for (i in 1:8) {
backlogts <- tbats(backlog)
fc2 <- forecast(backlogts, h=1)
fc2
fc_2 <- as.data.frame(fc2)
fc_2$i <- i # maybe you want to keep track of which iteration produced it?
datalist[[i]] <- fc_2 # add it to your list
backlog <- append(backlog,round(fc_2[1,1], digits = 2))
i <- i +1
}
forecast_data = do.call(rbind, datalist)
forecast_data$`Point Forecast` <- round(forecast_data$`Point Forecast` , digits = 3)
nextweekday <- function(date, wday) {
date <- as.Date(date)
diff <- wday - wday(date)
if( diff < 0 )
diff <- diff + 7
return(date + diff)
}
a <- tail(Data$Period_End_Date, n=1)
a <- as.Date(a, "%d-%b-%y")
b <- tail(Data$Project_ID, n=1)
Period_End_Date <- data.table(date=seq(as.Date(nextweekday(a,1)), by=7, length=8), key="date")
forecast_data = cbind(forecast_data, Period_End_Date)
names(forecast_data)[names(forecast_data) == 'date'] <- 'Period_End'
forecast_data$Period_End <- as.character(forecast_data$Period_End)
forecast_data$Project_ID <- b
forecast_data <- forecast_data[c(8,7,1,4,5)]
names(forecast_data)[names(forecast_data) == 'Lo 95'] <- 'Lower_Limit_95'
names(forecast_data)[names(forecast_data) == 'Hi 95'] <- 'Upper_Limit_95'
names(forecast_data)[names(forecast_data) == 'Point Forecast'] <- 'Point_Forecast'
}
},
warning = function(w) {},
error = function(e) {
forecast_data <- data.frame(Project_ID=character(),
Period_End=character(),
Point_Forecast=character(),
Lower_Limit_95=character(),
Upper_Limit_95=character(),
stringsAsFactors=FALSE)
print(paste("MY_ERROR: ",e))
})
I tried to print error print(paste("MY_ERROR: ",err)) under error = function(e), but it is not working
Is there anything I am missing. Please advice.

Answer 1

Does this help
foo <- function(x){
output <- tryCatch(x, error = function(e) e)
ifelse(is(output, "error"), "error", "no error")
}
foo() # error
foo(1) # no error
Alternatively, use purrr.
foo <- function(x){
x
}
foo_safe() # error
foo_safe(10)