Renaming factor levels without referring to the factor name-CodePudding

I have data with very messy factor level names, which are sometimes more than a sentence long. For that reason I would prefer to refer to the levels by number to rename them (instead of the usual factor level name). For the example data below, how could I rename the factor level (let's say to "G", "S1" and "S2"), without mentioning "gravel", "sandstone" or "siltstone"?

df <- data.frame(x = c("gravel", "sandstone", "siltstone"))

CodePudding user response：

You can change it with levels<-.

df <- data.frame(x = c("gravel", "sandstone", "siltstone"), stringsAsFactors = TRUE)
levels(df$x) 
#[1] "gravel"    "sandstone" "siltstone"

levels(df$x) <- c('G', 'S1', 'S2')
levels(df$x) 
#[1] "G"  "S1" "S2"

df
#   x
#1  G
#2 S1
#3 S2

CodePudding user response：

We may call factor with labels

df$x <- factor(df$x, labels = c("G", "S1", "S2"))
df$x
[1] G  S1 S2
Levels: G S1 S2

data

df <- data.frame(x = c("gravel", "sandstone", "siltstone"), stringsAsFactors = TRUE)