rankHospital.R

rankhospital <- function(state, outcome, num = "best") {

  # read outcome
  full_data <- read.csv("outcome-of-care-measures.csv", colClasses="character")
  
  column <- if (outcome == "heart attack") {
    "Hospital.30.Day.Death..Mortality..Rates.from.Heart.Attack"
  } else if (outcome == "heart failure") {
    "Hospital.30.Day.Death..Mortality..Rates.from.Heart.Failure"
  } else if (outcome == "pneumonia") {
    "Hospital.30.Day.Death..Mortality..Rates.from.Pneumonia"
  } else {
    stop("invalid outcome")
  }
  
  data_for_state <- full_data[full_data$State == state, c("Hospital.Name", column)]
  
  if (nrow(data_for_state) == 0) {
    stop("invalid state")	
  }
  
  data_for_state[,2] <- as.numeric(data_for_state[,2])
  ordered_data_for_state <- order(data_for_state[column], data_for_state$Hospital.Name, na.last=NA)
  
  if (num == "best") {
    as.character(data_for_state$Hospital.Name[ordered_data_for_state[1]])
  } else if (num == "worst") {
    as.character(data_for_state$Hospital.Name[ordered_data_for_state[length(ordered_data_for_state)]])
  } else if (is.numeric(num)) {
    as.character(data_for_state$Hospital.Name[ordered_data_for_state[num]])
  } else {
    stop("invalid num")
  }
}

# rankhospital("TX", "heart failure", 4)
# rankhospital("MD", "heart attack", "worst")
# rankhospital("MD", "heart attack", 4)