Sort column based on another that has already been sorted

I have a dataframe df that looks like this:

I need df$Value to be sorted so it’ll look like this:

Because it’s important to keep the first column’s order.

Would anyone know how to help me? I thank you in advance.

>Solution :

First set ID as factor, then arrange on Value.

library(dplyr)

df %>% mutate(ID = factor(ID, levels = unique(ID))) %>% arrange(ID, desc(Value))

  ID Value
1 37     6
2 37   -14
3 23     9
4 23   -17
5 51    13
6 51   -20