[R] data frame manipulation with condition

[Arnaud Gaboury]

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.

Arnaud Gaboury
 
A2CT2 Ltd.


-----Original Message-----
From: Uwe Ligges [mailto:ligges at statistik.tu-dortmund.de] 
Sent: vendredi 24 février 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




> and so on with other conditions.
>
> TY for any help.
>
> Trading
>
> A2CT2 Ltd.
>
>
> Arnaud Gaboury
>
> A2CT2 Ltd.
>
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