R/Rating.getCategories.R

In umatter/pvsR: Interact with the Project Vote Smart API for Scientific Research

##' Get categories that contain released ratings according to state
##' 
##' This function is a wrapper for the Rating.getCategories() method of the PVS API Rating class which dumps categories that contain released ratings according to state. The function sends a request with this method to the PVS API for all state IDs given as a function input, extracts the XML values from the returned XML file(s) and returns them arranged in one data frame.
##' @usage Rating.getCategories(stateId="NA")
##' @param stateId (optional) a character string or list of character strings with the stateId(s) (default: "NA", for national) (see references for details)
##' @return A data frame with a row for each rating and columns with the following variables describing the rating:\cr categories.category*.categoryId,\cr categories.category*.name.
##' @references http://api.votesmart.org/docs/Rating.html\cr
##' Use State.getStateIDs() to get a list of state IDs.\cr
##' See also: Matter U, Stutzer A (2015) pvsR: An Open Source Interface to Big Data on the American Political Sphere. PLoS ONE 10(7): e0130501. doi: 10.1371/journal.pone.0130501
##' @author Ulrich Matter <ulrich.matter-at-unibas.ch>
##' @examples
##' # First, make sure your personal PVS API key is saved as an option
##' # (options("pvs.key" = "yourkey")) or in the pvs.key variable:
##' \dontrun{pvs.key <- "yourkey"}
##' # get rating categories
##' \dontrun{rating <- Rating.getCategories()}
##' \dontrun{rating}

##' @export


Rating.getCategories <-
	function (stateId="NA") {

		# internal function
		Rating.getCategories.basic <- 
			function (.stateId) {
				
				request <-  "Rating.getCategories?"
				inputs  <-  paste("&stateId=",.stateId,sep="")
				output  <-  pvsRequest4(request,inputs)
				output$stateId <- .stateId
				
				return(output)
		}

		# Main function  
		output.list <- lapply(stateId, FUN= function (s) {
			Rating.getCategories.basic(.stateId=s)
		}
		)

		output.list <- redlist(output.list)
		output <- bind_rows(output.list)

		return(output)
		}