[R] create new column in a DF according to values from another column

[arun]

HI,
Try this:
 DF$Station[DF$number%in%c(1,7,11,16)]<-"V1"
 DF$Station[DF$number%in%c(4,14,20)]<-"V2"
 DF$Station[DF$number%in%c(3,17,19)]<-"V3"
 DF
#   number data Station
#1       1    1      V1
#2       4    2      V2
#3       7    3      V1
#4       3    4      V3
#5      11    5      V1
#6      16    6      V1
#7      14    7      V2
#8      17    8      V3
#9      20    9      V2
#10     19   10      V3

#or if you have more replacement values, then:
library(car)
DF <- data.frame(number=c(1,4,7,3,11,16,14,17,20,19),data=c(1:10))
DF1<-DF1
DF1$Station<-recode(DF1$number,"c(1,7,11,16)='V1';c(4,14,20)='V2';c(3,17,19)='V3'")
 DF1
#   number data Station
#1       1    1      V1
#2       4    2      V2
#3       7    3      V1
#4       3    4      V3
#5      11    5      V1
#6      16    6      V1
#7      14    7      V2
#8      17    8      V3
#9      20    9      V2
#10     19   10      V3


A.K.





----- Original Message -----
From: jeff6868 <geoffrey_klein at etu.u-bourgogne.fr>
To: r-help at r-project.org
Cc: 
Sent: Wednesday, September 26, 2012 6:49 AM
Subject: [R] create new column in a DF according to values from another column

Hi everyone,

I have a small problem in my R-code.

Imagine this DF for example:

DF <- data.frame(number=c(1,4,7,3,11,16,14,17,20,19),data=c(1:10))

I would like to add a new column "Station" in this DF. This new column must
be automatically filled with: "V1" or "V2" or "V3".
The choice must be done on the numbers (1st column).

For example, I would like to have "V1" in the column "Station" in the rows
where the numbers of the 1st column are: 1,7,11,16 ; then I would like to
have "V2" in the rows where the numbers are: 4,14,20 and finally "V3" in the
rows where the numbers are: 3,17,19.

I'm trying with "if" and something like this, but it's not working yet:
# For "V1":
if(DF$number %in% c(1,7,11,16)) {test$Station=="V1"}
# For "V2":
... 

So my final DF should look like this:

FINALDF <- data.frame(number=c(1,4,7,3,11,16,14,17,20,19),data=c(1:10),
Station=c("V1","V2","V1","V3","V1","V1","V2","V3","V2","V3"))

Could someone help me to finish this?

Thank you very much!!!





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