[R] Problems with intersections between two charcter vectors

[Berend Hasselman]

On 04-12-2013, at 07:52, snow <7146781 at qq.com> wrote:

> I'm a beginner with R.
> 
> I have two vectors in character format. I tried to get the intersection of these two vectors using intersect（）. But there is no result. The process is below:
>> a<-c("CREB2” ,“ELK1” ,“ELK4” ,“MYC” ,“NR4A1” ,“FOS” ,“SRF” ,“TAU” ,“STMN1” ,“CPLA2")> a[1] "CREB2” ,“ELK1” ,“ELK4” ,“MYC” ,“NR4A1” ,“FOS” ,“SRF” ,“TAU” ,“STMN1” ,“CPLA2"> b<-c("CAMK2”,“CPKC”,“CBL”,“STAT5A”,“FAK”,“ABL1”,“JUN”,“ELK1”,“MYC")> b[1] "CAMK2”,“CPKC”,“CBL”,“STAT5A”,“FAK”,“ABL1”,“JUN”,“ELK1”,“MYC"> intersect(a,b)character(0) 
> However when I tried intersect（）with another two vectors, it works. The example is like this:
>> c<-c("a", "b", "e", "c", "e", "f")> c[1] "a" "b" "e" "c" "e" "f"> d<-c("a", "g", "f", "b", "e")> d[1] "a" "g" "f" "b" "e"> intersect(c,d)[1] "a" "b" "e" "f" 
> I think something must be wrong in my way with first two vectors(a,b). Could anyone give me a kind help to tell me the reason for that? Thank you very much.
> 

What is displayed in Apple Mail is a mess since you posted in html.

It seems that some of your double quotes “ have been converted somewhere to typographic double quotes (or however they should be called).
Some of your output is weird: a[1] would display “CREB2” only and not what you show in your mail.

Doing it like this using proper ascii double quotes:

a<-c("CREB2" ,"ELK1" ,"ELK4" ,"MYC" ,"NR4A1" ,"FOS" ,"SRF" ,"TAU" ,"STMN1" ,"CPLA2")
b<-c("CAMK2","CPKC","CBL","STAT5A","FAK","ABL1","JUN","ELK1","MYC")

intersect(a,b)

displays:

[1] "ELK1" “MYC"

which is what you expected?

Berend


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