[R] Recode of text variables

Bill.Venables at csiro.au Bill.Venables at csiro.au
Thu Apr 2 01:39:09 CEST 2009


Here is one way

> x <- c("A", "B", "C", "D", "E", "A")
> x
[1] "A" "B" "C" "D" "E" "A"
> f <- factor(x)
> levels(f)
[1] "A" "B" "C" "D" "E"
> levels(f) <- c(rep("Treat1",2), rep("Treat2", 3))
> f
[1] Treat1 Treat1 Treat2 Treat2 Treat2 Treat1
Levels: Treat1 Treat2
> 

If you really want the charactre variable you can put

> x <- as.character(f)

_____

That's fascinating about Microsoft Access, but, uh... never mind. 


Bill Venables
http://www.cmis.csiro.au/bill.venables/ 


-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Andrew McFadden
Sent: Thursday, 2 April 2009 9:23 AM
To: r-help at r-project.org
Subject: [R] Recode of text variables

Hi all

I am trying to do a simple recode which I am stumbling on. I figure
there must be any easy way but haven't come across it.

Given data of A","B","C","D","E","A" it would be nice to recode this
into say three categories ie A and B becomes "Treat1", C becomes "Treat
2" and E becomes "Treat 3".

I tried the car library but it didn't seem to like text. Also it seems
you can only recode into two categories.


library(car)

x<-c("A","B","C","D","E","A")
x
recode(x, "c(A,B)='Treat 1'; else='Treat 2'")
recode(x, "1:2='A'; 3='B'")

In Microsoft access a simple way of recoding is to join two tables in a
query any simple way of doing the same in R?



Kind regards

Andy

Andrew McFadden MVS BVSc
Incursion Investigator
Investigation & Diagnostic Centres - Wallaceville Biosecurity New 
Zealand Ministry of Agriculture and Forestry

Phone 04 894 5600 Fax 04 894 4973 Mobile 029 894 5611 Postal address: 
Investigation and Diagnostic Centre- Wallaceville Box 40742 Ward St 
Upper Hutt


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