Hello,
Try the following.
fun <- function(x){
x[["adjusted_price"]] <- x[["price"]]
x[["adjusted_price"]][1] <- x[["price"]][1] - x[["adj_factor"]][1]
x
}
res <- do.call(rbind, lapply(split(dat, dat$id), fun))
rownames(res) <- NULL
res
Hope this helps,
Rui Barradas
Em 07-04-2014 12:12, Katherine Gobin escreveu:
Dear R forum
I have following data.frame
dat = data.frame(key = c("A", "B", "C", "D", "E", "E"), id = c("instru_A", "instru_B", "instru_B",
"instru_B", "instru_C", "instru_C"), price = c(101.38, 3.9306, 3.7488, 92.9624, 5.15, 96.1908), adj_factor = c(2.08, 2.5217, 2.5217, 2.5217, 3.08, 3.08))
dat
key id price adj_factor
1 A instru_A 101.3800 2.0800
2 B instru_B 3.9306 2.5217
3 C instru_B 3.7488 2.5217
4 D instru_B 92.9624 2.5217
5 E instru_C 5.1500 3.0800
6 E instru_C 96.1908 3.0800
This is just a part of big database and ids can appear any no of times.
# MY PROBLEM
I need to subtract adj_factor from the price, however only from the first id
only.
In case of instru_A, there is only 1 id, so 2.08 should be subtracted from
101.38.
The id "instru_B" is appearing 3 times. So in this case, adj_factor = 2.5217
should be subtracted from 3.9306 and rest should remain same.
Similarly, id "instru_C" is appearing 2 times, hence the adj_factor = 3.08
should be subtracted from 5.15.
Effectively I am looking for
dat_new
key id price adj_factor adjusted_price
1 A instru_A 101.3800 2.0800 99.3000 # price adjusted
2 B instru_B 3.9306 2.5217 1.4089 # price adjusted
3 C instru_B 3.7488 2.5217 3.7488
4 D instru_B 92.9624 2.5217 92.9624
5 E instru_C 5.1500 3.0800 2.0700 # price adjusted
6 E instru_C 96.1908 3.0800 96.1908
I tried something like
adj_price = function(id, price, adj_factor)
{
id_length = length(id)
if(id_length == 1)
{
(adjusted_price = price-adj_factor)
}
if(id_length == 2)
{
(adjusted_price = c(price[1]-adj_factor[1], price[2]))
}
if(id_length > 2)
{
(adjusted_price = c(price[1]-adj_factor[1],price[2:id_length]))
}
return(adjusted_price)
}
(final_price = adj_price(dat$id, dat$price, dat$adj_factor))
(final_price = adj_price(dat$id, dat$price, dat$adj_factor))
[1] 99.3000 3.9306 3.7488 92.9624 5.1500 96.1908
Kindly advise
Regards
Katherine
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