r - For 循环 : replacement has one row more than data

Question

我是 R 的初学者，遇到了问题。任何帮助将不胜感激!
当我在以下(简化的)情况下应用 for 循环时，我收到一条错误消息，指出“替换有 5 行，数据有 4”

Country <- c("Germany", "France", "Italy", "Spain")
Unemploy <- c(2, 3, 4, 10)
Growth <- c(2, 7, 6, 9)
data <- data.frame(Country, Unemploy, Growth)

for (i in data$Country) {
     if (identical(data$Country[i], "France")) {
          data$Growth[i] <- "5"
     } else {
          data$Growth[i] <- "2"
     }
}

发出以下消息:

Error in `$<-.data.frame`(`*tmp*`, "Growth", value = c("2", "2", "2",  : 
replacement has 5 rows, data has 4

Answer 1

使用 ifelse反而

data[ ,"Growth"] <- ifelse(data[ , "Country"] == "France", "5", "2")