rankall.R

rankall <- function(outcome,num='best') {
	data<-read.csv('outcome-of-care-measures.csv')
	outcomes<-c('heart attack', 'heart failure', 'pneumonia')
	indices<-c(11,17,23)
	
	if (!outcome %in% outcomes) stop('invalid outcome')
	
	i<-indices[match(outcome,outcomes)]
	hospitals<-data[, c(2,7,i)]
	hospitals[,3]<-as.numeric(as.character(hospitals[,3]))
	hospitals<-na.omit(hospitals)
	names(hospitals) <- c('hospital','state','rate')

	if (num == "best") {
		num <- 1
	} else if (num == "worst") {
		num <- nrow(hospitals)
	} else {
		num <- as.numeric(num)
		if (is.na(num)) {
			stop('invalid num')
		} else if (num > nrow(hospitals)) {
			return(NA)
		}
	}
	
	results <- NULL
	
	for(state in levels(hospitals$state)) {
		hospitals_for_state <- hospitals[hospitals$state == state,]
		
		if (num == "worst") {
			n <- nrow(hospitals_for_state)
		} else {
			n <- num
		}
		result <- hospitals_for_state[order(hospitals_for_state$rate, hospitals_for_state$hospital), c(1,2)][n,]
		result$state <- rep(state,nrow(result))
		results <- rbind(results, result)
	}
	
	rownames(results) <- NULL
	return(results)
}