R/Candidates.getByElection.R

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

##' Get a list of candidates according to the election they are running for
##'  
##' This function is a wrapper for the Candidates.getByElection() method of the PVS API Candidates class which grabs a list of candidates according to the election they are running for. The function sends a request with this method to the PVS API for all electionIDs and stageIDs given as a function input, extracts the XML values from the returned XML file(s) and returns them arranged in one data frame.
##' @usage Candidates.getByElection(electionId, stageId=NULL)
##' @param electionId a character string or list of character strings with the election ID(s) (see references for details)
##' @param stageId (optional) a character string or list of character strings with the stage ID(s) (default: all)
##' @return A data frame with a row for each candidate and columns with the following variables describing the candidate:\cr candidateList.candidate*.candidateId,\cr candidateList.candidate*.firstName,\cr candidateList.candidate*.nickName,\cr candidateList.candidate*.middleName,\cr candidateList.candidate*.preferredName,\cr candidateList.candidate*.lastName,\cr candidateList.candidate*.suffix,\cr candidateList.candidate*.title,\cr candidateList.candidate*.ballotName,\cr candidateList.candidate*.electionParties,\cr candidateList.candidate*.electionStatus,\cr candidateList.candidate*.electionStage,\cr candidateList.candidate*.electionDistrictId,\cr candidateList.candidate*.electionDistrictName,\cr candidateList.candidate*.electionOffice,\cr candidateList.candidate*.electionOfficeId,\cr candidateList.candidate*.electionStateId,\cr candidateList.candidate*.electionOfficeTypeId,\cr candidateList.candidate*.electionYear,\cr candidateList.candidate*.electionSpecial,\cr candidateList.candidate*.electionDate,\cr candidateList.candidate*.officeParties,\cr candidateList.candidate*.officeStatus,\cr candidateList.candidate*.officeDistrictId,\cr candidateList.candidate*.officeDistrictName,\cr candidateList.candidate*.officeStateId,\cr candidateList.candidate*.officeId,\cr candidateList.candidate*.officeName,\cr candidateList.candidate*.officeTypeId,\cr candidateList.candidate*.runningMateId,\cr candidateList.candidate*.runningMateName
##' @references http://api.votesmart.org/docs/Candidates.html\cr 
##' Use Election.getElectionByYearState() or Election.getElectionByZip() to get election ID(s).\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 a list of candidates for certain election IDs
##' \dontrun{candidates <- Candidates.getByElection(list(2582,2646))}
##' \dontrun{candidates}
##' @export

Candidates.getByElection <-
	function (electionId, stageId=NULL) {
		
		if (length(stageId)==0) {
			# internal function
			Candidates.getByElection.basic1 <- 
				function (.electionId) {
					
					request <-  "Candidates.getByElection?"
					inputs  <-  paste("&electionId=",.electionId,sep="")
					output  <-  pvsRequest4(request,inputs)
					output$electionId <- .electionId
					return(output)
			}

			# Main function  
			output.list <- lapply(electionId, FUN= function (s) {
				Candidates.getByElection.basic1(.electionId=s)
			}
			)

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

		} else {
			
			# internal function
			Candidates.getByElection.basic2 <- 
				function (.electionId, .stageId) {
					request <-  "Candidates.getByElection?"
					inputs  <-  paste("&electionId=",.electionId, "&stageId=", .stageId, sep="")
					output  <-  pvsRequest4(request,inputs)
					output$electionId <- .electionId
					output$stageId.input <- .stageId
					
					return(output)
				}
			
			
			# Main function  
			output.list <- lapply(electionId, FUN= function (s) {
				lapply(stageId, FUN= function (c) {
					Candidates.getByElection.basic2( .electionId=s, .stageId=c)
				}
				)
			}
			)
			
			output.list <- redlist(output.list)
			output <- bind_rows(output.list)
			
			# Avoids, that output is missleading, because stageId is already given in request-output, but also a
			# additionally generated (as stageId.input). Problem exists because some request-outputs might be empty
			# and therefore only contain one "stageId" whereas the non-empty ones contain two. (see basic function)
			output$stageId[c(as.vector(is.na(output$stageId)))] <- output$stageId.input[as.vector(is.na(output$stageId))]
			output$stageId.input <- NULL
		}
		return(output)
	}