顺序错误(datastate$c):参数1不是向量

best <- function(state, outcome) {
    data = read.csv("outcome-of-care-measures.csv", colClasses="character")
    data[, 11] <- as.numeric(data[, 11])
    data[, 17] <- as.numeric(data[, 17])
    data[, 23] <- as.numeric(data[, 23])
    if (outcome == "heart attack") { 
        dataset <- data[,c(2,7,11)]
    } else if (outcome == "heart failure") {
        dataset <- data[,c(2,7,17)]
    } else if (outcome == "pneumonia") {
        dataset <- data[,c(2,7,23)]
    }
    dataset<- na.omit(dataset)
    names(dataset)<- c("a","State","c")

    datastates <- split(dataset, dataset$State)
    datastate <- datastates$state
    order.h <- order(datastate$c)

    answer <- datastate[order.h,]
    answer [1,1]
}
best <- function(state, outcome) {
    data = r