How can I sort only some factors?

[Watakushi]

Hello community.

I want to sort factors but there are a lot of factors, so I want to use minimum effort.

How can I sort them like "factor(data, levels=c("A", "B", and the others))"?

Thank you.

[MarekGierlinski]

forcats::fct_other() was designed exactly for this purpose.

library(forcats)
x <- factor(rep(LETTERS[1:9], times = c(40, 10, 5, 27, 1, 1, 1, 1, 1)))
fct_other(x, keep = c("A", "B"))

 [1] A     A     A     A     A     A     A     A     A     A     A     A     A     A     A     A     A     A     A     A     A     A    
[23] A     A     A     A     A     A     A     A     A     A     A     A     A     A     A     A     A     A     B     B     B     B    
[45] B     B     B     B     B     B     Other Other Other Other Other Other Other Other Other Other Other Other Other Other Other Other
[67] Other Other Other Other Other Other Other Other Other Other Other Other Other Other Other Other Other Other Other Other Other
Levels: A B Other

[Watakushi]

Thank you for your prompt reply.

But excuse me, maybe I couldn't explain well, I want to make first and second legend factor be in front of the other legends, and the other legends can line up randomly in line plot using ggplot.

How can I extract two legend factors from a lot of legends and place them at the top of the other legends and sort the rest so that they are in default alphabetical order?

Thank you.

[MarekGierlinski]

Do you mean something like this?

library(forcats)

x <- factor(rep(LETTERS[1:9], times = c(40, 10, 5, 27, 1, 1, 1, 1, 1)))
fct_relevel(x, c("C", "I"))
#>  [1] A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A
#> [39] A A B B B B B B B B B B C C C C C D D D D D D D D D D D D D D D D D D D D D
#> [77] D D D D D D E F G H I
#> Levels: C I A B D E F G H

Now levels C and I are before all others.

[Watakushi]

I could complete an easy-to-read line chart legend using the "fct_relevel" suggested by you two !

Thank you so much !