how to add a column from another dataset with "merge"

Hi,
You could use sort=FALSE in ?merge()
d1<-data.frame(id=c(9,8,6,5,4,3,1))
d2<-data.frame(id=c(9,8,6),age=c(46,56,52))
?d<-merge(d1,d2,all.x=TRUE,sort=FALSE)
#or
library(plyr)
join(d1,d2,by="id",type="full")
#? id age
#1? 9? 46
#2? 8? 56
#3? 6? 52
#4? 5? NA
#5? 4? NA
#6? 3? NA
#7? 1? NA
A.K.

----- Original Message -----
From: Pete Brecknock <Peter.Brecknock at bp.com>
To: r-help at r-project.org
Cc: 
Sent: Friday, December 7, 2012 9:12 AM
Subject: Re: [R] how to add a column from another dataset with "merge"

kiotoqq wrote

I want to add a shorter column to my dataset with the function "merge", 
it
should be filled with NAs wo be as long as the other colums, like this:

id? ? age
9? ? 46
8? ? 56
6?  52
5?  NA
4?  NA
3? NA
1? NA

i did this:
pa1 <- merge(pa1, an1, by="mergeid")

and it says "'by' must specify uniquely valid column(s)"

how about ...

#Data
d1<-data.frame(id=c(9,8,6,4,4,3,1))
d2<-data.frame(id=c(9,8,6),age=c(46,56,52))

# Left Merge
d<-merge(d1,d2,all.x=TRUE)

# Reorder
d[order(d$id,decreasing=TRUE),]

HTH

Pete



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