r语言 - 如何在数据帧中将列的类型从字符更改为序数?

Question

我想将列的类型从字符更改为顺序，级别为no。一年中的月数(即:12)不。年(即3年)。我的数据帧与下面的类似:

month <- c("Jan", "Feb", "Mar", "Apr", "May", "June", "July", "Aug", "Sept", "Oct", "Nov", "Dec")
year <- c(rep(2020,5),rep(2021,5),rep(2022,2))
df <- data.frame(month,year)
df$month <- as.factor(df$month)
df$year <-as.factor(df$year)

如何将这里的级别更改为no ?几个月和几年?

Answer 1

我们可以用labels

df$month <- factor(df$month, levels = unique(df$month), labels = 1:12)
df$year <- factor(df$year, levels = sort(unique(df$year)), 
labels = seq_along(sort(unique(df$year))))