rearrange a variable based on another variable - r

Question

Data:
set.seed(25)
df<- data.frame(rank=round(rnorm(10)),category=round(runif(10)),v=round(rnorm(10)))
rank category v
1 0 0 1
2 -1 0 -1
3 -1 0 1
4 0 0 2
5 -2 0 -1
6 0 0 1
7 2 0 0
8 1 1 0
9 0 1 2
10 0 0 -2
I want the variable "v" follows the same ranking as the variable "rank1", within each category. My question is how could I create the desired variable "v1"?
Desired output:
df <- transform(df, rank1 = ave(v, category, FUN = function(x) rank(x, ties.method = "random")))
rank category v rank1 v1
1 0 0 1 6 -1
2 -1 0 -1 3 1
3 -1 0 1 7 -1
4 0 0 2 8 -2
5 -2 0 -1 2 1
6 0 0 1 5 0
7 2 0 0 4 1
8 1 1 0 1 2
9 0 1 2 2 0
10 0 0 -2 1 2

Answer 1

So I get the desired result:
set.seed(25)
df <- data.frame(rank=round(rnorm(10)), category=round(runif(10)), v=round(rnorm(10)))
df <- transform(df, rank1 = ave(v, category, FUN = function(x) rank(x, ties.method = "random")))
df$v1 <- NA
for (i in unique(df$category)) {
df$v1[df$category==i] <- sort(df$v[df$category==i], decrea=TRUE)[df$rank1[df$category==i]]
}
The idea is going through the categories and apply the order given by rank1 to the sorted part of the vector v.