grouping elements of a data frame

Hi everyone,

I have a question on selecting and grouping elements of a data frame. For example:

A.df<- [ a c 0.9
            b  x 0.8
            b z 0.5
            c y 0.9
            c x 0.7
            c z 0.6]

That is not R code. Matlab?, Python?

I want to create a list of a data frame that gives me the unique values of column 1 of A.df so that i can create intersects. That is:

B[a]<- [ c 0.9]

B[b]<- [ x 0.8
            z 0.5]

B[c]<- [ y 0.9
            x 0.7
            z 0.6]


B[c] n B[b] <- c(x,z)

That's some sort of coded message? We are supposed to know what the "n" operation will do when assigned a vector?


Assuming your really do have a dataframe named B:

intersect(B$c, B$b)

Please code up examples in R in the future.

David Winsemius
Alameda, CA, USA

Hi,
Try this:
The last part was not clear.
A.df<-read.table(text="
??? ??? a c 0.9
??????????? b? x 0.8
??????????? b z 0.5
??????????? c y 0.9
??????????? c x 0.7
??????????? c z 0.6
",sep="",header=FALSE,stringsAsFactors=FALSE)
?lst1<-split(A.df[,-1],A.df$V1)
lst1
#$a
#? V2? V3
#1? c 0.9
#
#$b
#? V2? V3
#2? x 0.8
#3? z 0.5
#
#$c
#? V2? V3
#4? y 0.9
#5? x 0.7
#6? z 0.6


A.K.



----- Original Message -----
From: Nuri Alpay Temiz <alpaytemiz at outlook.com>
To: R-help at r-project.org
Cc: 
Sent: Tuesday, January 15, 2013 12:10 PM
Subject: [R] grouping elements of a data frame

Hi everyone,

I have a question on selecting and grouping elements of a data frame. For example:

A.df<- [ a c 0.9
? ? ? ? ? ?  b? x 0.8
? ? ? ? ? ?  b z 0.5
? ? ? ? ? ?  c y 0.9
? ? ? ? ? ?  c x 0.7
? ? ? ? ? ?  c z 0.6]


I want to create a list of a data frame that gives me the unique values of column 1 of A.df so that i can create intersects. That is:

B[a]<- [ c 0.9]

B[b]<- [ x 0.8
? ? ? ? ? ?  z 0.5]

B[c]<- [ y 0.9
? ? ? ? ? ?  x 0.7
? ? ? ? ? ?  z 0.6]


B[c] n B[b] <- c(x,z)


How can I accomplish this?

Thanks,
Al
? ? ? ? ? ? ? ? ? ? 
? ? ? ? ? ? 
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