data frame manipulation with condition

mult <- c(AA = 10, BB = 25, CC=1, DD=15)
mult[df$x]

df$y * mult[df$x]

df<- data.frame(x = c("AA","BB","CC","AA","DD","DD"), y = 1:6)
mult <- c(AA = 10, BB = 25,DD=15)
df$y <- df$y * mult[df$x]
df

? x ?y
1 AA 10
2 BB 50
3 CC 45
4 AA 40
5 DD NA
6 DD NA

My df is in fact much more longer than the chosen example shown here. It seems your tip didn't do the job.
I am expecting this as result :

df

? x ?y
1 AA 10 ?----> if df$x==AA, df$y<-1*10
2 BB 50 ? ----> if df$x==BB, df$y<-2*25
3 CC 3 ? ? ? ? NOTHING
4 AA 40 ? ?----> if df$x==AA, df$y<-4*10
5 DD 75 ? ----> if df$x==DD, df$y<-5*15
6 DD 90 ? ----> if df$x==DD, df$y<-6*15

Arnaud Gaboury

A2CT2 Ltd.

-----Original Message-----
From: Uwe Ligges [mailto:ligges at statistik.tu-dortmund.de]
Sent: vendredi 24 f?vrier 2012 17:07
To: Arnaud Gaboury
Cc: r-help at r-project.org
Subject: Re: [R] data frame manipulation with condition



On 24.02.2012 16:59, Arnaud Gaboury wrote:

TY Uwe,

So I will have to write a line for each condition? Right?

In fact I was trying to do something with apply in one line, but couldn't achieve any result. In fact, all my transformation will be multiplying one object by a specific number according to the value of df$x.

In that case:

mult <- c(AA = 10, BB = 25)

Then:


df$y <- df$y * mult[df$x]


Uwe Ligges

Arnaud Gaboury

A2CT2 Ltd.


-----Original Message-----
From: Uwe Ligges [mailto:ligges at statistik.tu-dortmund.de]
Sent: vendredi 24 f?vrier 2012 16:33
To: Arnaud Gaboury
Cc: r-help at r-project.org
Subject: Re: [R] data frame manipulation with condition



On 24.02.2012 16:25, Arnaud Gaboury wrote:

Dear list,

n00b question, but still can't find any easy answer.

Here is a df:

Change

df<-data.frame(cbind(x=c("AA","BB","CC","AA"),y=1:4))

to

? ?df<- data.frame(x = c("AA","BB","CC","AA"), y = 1:4)

to make your object a sensible data.frame.

df

? ? ?x y
1 AA 1
2 BB 2
3 CC 3
4 AA 4


I want to modify this df this way :
? ?if df$x=="AA" then df$y=df$y*10

df$y[df$x=="AA"]<- df$y[df$x=="AA"] * 25

...


Uwe Ligges

? ?if df$x=="BB" then df$y=df$y*25