Re: [R] lookup not working properly

From: Sarah Goslee <sarah.goslee_at_gmail.com>
Date: Tue, 12 Apr 2011 11:42:51 -0400

Dimitri,

It isn't clear to me exactly what you are trying to do, but this might be closer.
Note the stringsAsFactors argument I added to data.frame: I don't think you are likely to want factors for this application. Also, it's a bad idea to create a
variable named c since that is the name of a function.

# my reference data frame:
myref<-data.frame(a=c("ba ba","ca ca","da da", "lake lake, a", "lake lake, b","lake of","lama ca, a","lama ca, b","ma ma"), b=c("ba ba","ca ca","OTHER", "lake lake, a", "lake lake, b","lake of","lama ca, a","lama ca, b","OTHER"), stringsAsFactors=FALSE)

# my data:
temp<-data.frame(c=c(rep("ba ba",3),rep("ca ca",3),rep("da da",3),rep("lake lake, a",3),
 rep("lake lake, b",3),rep("lake of",3),rep("lama ca, a",3),rep("lama ca ,b",3),rep("ma ma",3)), stringsAsFactors=FALSE)

newdata <- merge(myref, temp, by.x="a", by.y="c", all.x=FALSE, all.y=TRUE)

Sarah

On Tue, Apr 12, 2011 at 11:17 AM, Dimitri Liakhovitski <dimitri.liakhovitski_at_gmail.com> wrote:
> Hello!
>
> Below is my exmample. "myref" is my reference data frame with columns a and b.
> "temp" is my data with column c analogous to column a in "myref".
> I am trying to create a new variable b - in "temp" - that matches
> values from b in "myref" to values in c. If you look at the resulting
> data frame (temp - at the bottom), you'll notice that rows 19-24 are
> incorrect.
> How could one fix it?
> Thanks a lot!
>
> # my reference data frame:
> a=c("ba ba","ca ca","da da", "lake lake, a", "lake lake, b","lake
> of","lama ca, a","lama ca, b","ma ma")
> b=c("ba ba","ca ca","OTHER", "lake lake, a", "lake lake, b","lake
> of","lama ca, a","lama ca, b","OTHER")
> myref<-data.frame(a=a, b=b)
> (myref)
>
> # my data:
> c<-c(rep("ba ba",3),rep("ca ca",3),rep("da da",3),rep("lake lake, a",3),
>  rep("lake lake, b",3),rep("lake of",3),rep("lama ca, a",3),rep("lama
> ca ,b",3),rep("ma ma",3))
> temp<-data.frame(c=c)
> (temp)
>
> ### Matching:
> temp$b<-myref[temp$c,"b"]
> (temp)
>
> --
> Dimitri Liakhovitski
> Ninah Consulting
> www.ninah.com
>

-- 
Sarah Goslee
http://www.functionaldiversity.org

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Received on Tue 12 Apr 2011 - 15:47:28 GMT

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