[R] Creating Enumerated Variables

[John Kane]

I think this is simpler but still not all that clean.
===============================================================
xx  <- structure(list(ID = 1:9, Age = c(10L, 10L, 10L, 11L, 11L, 11L,
10L, 10L, 11L), School = c(1L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 2L
), Grade = c(98L, 97L, 92L, 90L, 80L, 70L, 80L, 79L, 70L)), .Names = c("ID",
"Age", "School", "Grade"), class = "data.frame", row.names = c(NA,
-9L))

library(reshape)

(rr <- cast(xx, Age + School  ~ ., length))


mylist <- NULL
for(i in 1:length(rr[,3])) {
mylist[[i]] <- seq(rr[i,3])
}

ecount <- unlist(mylist)

cbind(xx[order(xx[,3]),], ecount)


================================================================

--- On Thu, 7/15/10, Dennis Murphy <djmuser at gmail.com> wrote:

> From: Dennis Murphy <djmuser at gmail.com>
> Subject: Re: [R] Creating Enumerated Variables
> To: "jdellava" <jdellava at vcuHI.edu>
> Cc: r-help at r-project.org
> Received: Thursday, July 15, 2010, 5:08 PM
> Hi:
> 
> I sincerely hope there's an easier way, but one method to
> get this is as
> follows,
> with d as the data frame name of your test data:
> 
> d <- d[order(with(d, Age, School, rev(Grade))), ]
> d$Count <- do.call(c, mapply(seq, 1, as.vector(t(with(d,
> table(Age,
> School))))))
> d
> 
> > d
>   ID Age School Grade Count
> 1  1  10      1   
> 98     1
> 3  3  10      1   
> 92     2
> 7  7  10      1   
> 80     3
> 8  8  10      1   
> 79     4
> 2  2  10      2   
> 97     1
> 4  4  11      1   
> 90     1
> 5  5  11      1   
> 80     2
> 6  6  11      2   
> 70     1
> 9  9  11      2   
> 70     2
> 
> 
> The code to get the count is a little convoluted:
>     - first, find the frequency table of Age and
> School, transpose it and
> then unlist into a vector
>     - use mapply to generate a sequence for each
> group from 1 up to its
> group count; mapply()  is necessary to use the counts
> as a vector argument.
> This returns a list of sequences.
>     - do.call() applies a function (here, c) to
> an input list, yielding the
> vector of groupwise indices we wanted. Basically, it
> flattens the list. This
> is what we assign to d$Count.
> 
> Side note: I didn't get the correct ordering the first
> time, but I did the
> second time (2.11.1 64bit, Windows 7).
> 
> HTH,
> Dennis
> 
> On Thu, Jul 15, 2010 at 7:45 AM, jdellava <jdellava at vcu.edu>
> wrote:
> 
> >
> > Hi,
> >
> > I am trying to create a variable counting the number
> of individuals based
> > on
> > two variables. I am able to do it or one variable, but
> not two. In SAS I
> > was
> > able to sort by two variables and use a first.
> statement to create the
> > counts based on both. Here is an example:
> >
> > What I have
> > ID      Age       
>      School       
>   Grade
> > 1       10   
>           1     
>              
>    98
> > 2       10   
>           2     
>              
>    97
> > 3       10   
>           1     
>              
>    92
> > 4       11   
>           1     
>              
>    90
> > 5       11   
>           1     
>              
>    80
> > 6       11   
>           2     
>              
>    70
> > 7       10   
>           1     
>              
>    80
> > 8       10   
>           1     
>              
>    79
> > 9       11   
>           2     
>              
>    70
> >
> > What I need
> > ID      Age       
>      School       
>   Grade   School Count
> > 1       10   
>           1     
>              
>    98         
>     1
> > 3       10   
>           1     
>              
>    92         
>     2
> > 7       10   
>           1     
>              
>    80         
>     3
> > 8       10   
>           1     
>              
>    79         
>     4
> > 2       10   
>           2     
>              
>    97         
>     1
> > 4       11   
>           1     
>              
>    90         
>     1
> > 5       11   
>           1     
>              
>    80         
>     2
> > 6       11   
>           2     
>              
>    70         
>     1
> > 9       11   
>           2     
>              
>    70         
>     2
> >
> > I want to create counts of individuals age 10 in
> school 1 then age 10 in
> > school two (the what I need set)
> >
> > Anyway to do this?
> >
> > Thank you.
> >
> > --
> > View this message in context:
> > http://r.789695.n4.nabble.com/Creating-Enumerated-Variables-tp2290262p2290262.html
> > Sent from the R help mailing list archive at
> Nabble.com.
> >
> > ______________________________________________
> > 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.
> >
> 
>     [[alternative HTML version deleted]]
> 
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained,
> reproducible code.
>