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
> [[alternative HTML version deleted]]
>
>
>
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