#' @title ERP Rates
#'
#' @description Provides the ERP rates for all vehicle types across all timings and all zones.
#'
#' @param api_key API key for LTA's Datamall
#' @return A dataframe containing ERP rates for each vehicle type, ERP rate timing, and zone.
#' @examples
#' \donttest{
#' getERPRates(mykey)
#' }
#' @import httr
#' @export getERPRates
getERPRates <- function(api_key) {
result <- httr::GET("http://datamall2.mytransport.sg/ltaodataservice/ERPRates",
httr::add_headers(AccountKey = api_key))
if (httr::http_status(result)$category != "Success") {
message("Unsuccessful API call for ERP rates data. Please check your parameters or connection.")
return(result)
} else {
message("Successful API call for ERP rates data. Processing page 1...")
}
output <- data.frame(matrix(nrow = 0, ncol = 7))
erp_list <- httr::content(result)[[2]]
for (i in 1:length(erp_list)) {
interim <- erp_list[[i]]
interim[sapply(interim, is.null)] <- 0
output <- rbind(output, t(unlist(interim)))
}
names(output) <- names(unlist(erp_list[[1]]))
num <- 2
while(length(erp_list) > 499) {
result <- httr::GET(paste("http://datamall2.mytransport.sg/ltaodataservice/ERPRates", "?$skip=", (num-1)*500, sep=""),
httr::add_headers(AccountKey = api_key))
if (httr::http_status(result)$category != "Success") {
message("Unsuccessful API call for ERP rates data. Please check your parameters or connection.")
return(result)
} else {
message("Successful API call for ERP rates data. Processing page ", num, "...")
}
output0 <- data.frame(matrix(nrow = 0, ncol = 7))
erp_list <- httr::content(result)[[2]]
for (i in 1:length(erp_list)) {
interim <- erp_list[[i]]
interim[sapply(interim, is.null)] <- 0
output0 <- rbind(output0, t(unlist(interim)))
}
output <- rbind(output, output0)
num <- num + 1
}
for (col in colnames(output)) {
output[[col]] <- as.character(output[[col]])
}
message('API call completed! Number of ERP rates: ', nrow(output))
return(output)
}
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.