Dear R-helpers,
I have a data frame with 3 variables, each record is a unique combination of
the three variables. I would like to count the number of unique values of v3
in each v1, and save it as a new variable v4 in the same data frame.
e.g.
df1
[v1] [v2] [v3]
[1,] "a" "C" "1"
[2,] "b" "C" "2"
[3,] "c" "B" "3"
[4,] "a" "B" "3"
[5,] "b" "A" "2"
[6,] "c" "A" "1"
In this case, the 4th column would become (2, 1, 2, 2, 1, 2).
Could someone tell me how to do this?
regards,
Lijiang
--
[[alternative HTML version deleted]]
On Oct 16, 2008, at 1:27 AM, Lijiang Guo wrote:> Dear R-helpers, > > I have a data frame with 3 variables, each record is a unique > combination of > the three variables. I would like to count the number of unique > values of v3 > in each v1, and save it as a new variable v4 in the same data frame. > e.g. > df1 > [v1] [v2] [v3] > [1,] "a" "C" "1" > [2,] "b" "C" "2" > [3,] "c" "B" "3" > [4,] "a" "B" "3" > [5,] "b" "A" "2" > [6,] "c" "A" "1" > > In this case, the 4th column would become (2, 1, 2, 2, 1, 2).> txt <- ' v1 v2 v3 + "a" "C" "1" + "b" "C" "2" + "c" "B" "3" + "a" "B" "3" + "b" "A" "2" + "c" "A" "1"' df1 <- read.table(textConnection(txt), header=TRUE) grps <- tapply(df1$v3, df1$v1,FUN=table) # > sapply(grps,length) # a b c # 2 1 2 df1$v4 <- sapply(grps,length)[df1$v1] df1> v1 v2 v3 v4 > 1 a C 1 2 > 2 b C 2 1 > 3 c B 3 2 > 4 a B 3 2 > 5 b A 2 1 > 6 c A 1 2-- David Winsemius, MD Heritage Labs> > Could someone tell me how to do this? > > regards, > Lijiang > > > -- > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.
How about this:> df1=data.frame(v1=c(1,1,2,3,2,4,1)) > df1$v2 <- ave(df1$v1,df1$v1,FUN=length) > df1v1 v2 1 1 3 2 1 3 3 2 2 4 3 1 5 2 2 6 4 1 7 1 3 On Thu, Oct 16, 2008 at 1:27 PM, Lijiang Guo <lijguo at gmail.com> wrote:> Dear R-helpers, > > I have a data frame with 3 variables, each record is a unique combination of > the three variables. I would like to count the number of unique values of v3 > in each v1, and save it as a new variable v4 in the same data frame. > e.g. > df1 > [v1] [v2] [v3] > [1,] "a" "C" "1" > [2,] "b" "C" "2" > [3,] "c" "B" "3" > [4,] "a" "B" "3" > [5,] "b" "A" "2" > [6,] "c" "A" "1" > > In this case, the 4th column would become (2, 1, 2, 2, 1, 2). > > Could someone tell me how to do this? > > regards, > Lijiang > > > -- > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >-- HUANG Ronggui, Wincent Tel: (00852) 3442 3832 Ph.D. Candidate, CityU of HK Master of sociology, Fudan University, China Bachelor of Social Work, Fudan University, China Personal homepage: http://ronggui.huang.googlepages.com/
On 10/16/2008 1:27 AM, Lijiang Guo wrote:> Dear R-helpers, > > I have a data frame with 3 variables, each record is a unique combination of > the three variables. I would like to count the number of unique values of v3 > in each v1, and save it as a new variable v4 in the same data frame. > e.g. > df1 > [v1] [v2] [v3] > [1,] "a" "C" "1" > [2,] "b" "C" "2" > [3,] "c" "B" "3" > [4,] "a" "B" "3" > [5,] "b" "A" "2" > [6,] "c" "A" "1" > > In this case, the 4th column would become (2, 1, 2, 2, 1, 2). > > Could someone tell me how to do this?df1 <- data.frame(V1=rep(c('a','b','c'),2), V2=rep(c('C','B','A'),each=2), V3=c(1,2,3,3,2,1)) df1$V4 <- with(df1, ave(V3, V1, FUN = function(x){length(unique(x))})) df1 V1 V2 V3 V4 1 a C 1 2 2 b C 2 1 3 c B 3 2 4 a B 3 2 5 b A 2 1 6 c A 1 2 ?ave ?unique ?length> regards, > Lijiang > > -- > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.-- Chuck Cleland, Ph.D. NDRI, Inc. (www.ndri.org) 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 512-0171 (M, W, F) fax: (917) 438-0894