data frame manipulation with conditions

Dear list,

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

Here is a df:

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

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

I want to modify this df this way :
?if df$x=="AA" then df$y=df$y*10
?if df$x=="BB" then df$y=df$y*25

and so on with other conditions.

TY for any help.

Trading

A2CT2 Ltd.

Dear list,

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

Here is a df:

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

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

I want to modify this df this way :
?if df$x=="AA" then df$y=df$y*10
?if df$x=="BB" then df$y=df$y*25

and so on with other conditions.

TY for any help.

Trading

A2CT2 Ltd.

TY Elai for your answer. One solution has been given earlier in this list by Sarah Goslee and William Dunlap.

Arnaud Gaboury

A2CT2 Ltd.


-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of ilai
Sent: vendredi 24 f?vrier 2012 20:14
To: A2CT2 Trading
Cc: r-help at r-project.org
Subject: Re: [R] data frame manipulation with conditions

On Fri, Feb 24, 2012 at 8:11 AM, A2CT2 Trading <trading at a2ct2.com> wrote:

Dear list,

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

Here is a df:

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

# No, your y is a factor
?str(df)
'data.frame': ? 4 obs. of ?2 variables:
?$ x: Factor w/ 3 levels "AA","BB","CC": 1 2 3 1 ?$ y: Factor w/ 4 levels "1","2","3","4": 1 2 3 4

# You want to remove the cbind

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

'data.frame': ? 4 obs. of ?2 variables:
?$ x: Factor w/ 3 levels "AA","BB","CC": 1 2 3 1 ?$ y: int ?1 2 3 4

I want to modify this df this way :
?if df$x=="AA" then df$y=df$y*10
?if df$x=="BB" then df$y=df$y*25

and so on with other conditions.

?df$y<- df$y * c(10,25,.5)[df$x]
[1] 10.0 50.0 ?1.5 40.0
?# 1*10 2*25 3*.5 4*10

HTH

Elai

TY for any help.

Trading

A2CT2 Ltd.