Hi,
Another way of doing may be like this;
a <- c("d", "d", "j", "f", "e", "g", "f", "f", "i", "g")
b <- c("a", "g", "d", "f", "g", "a", "f", "a", "b", "g")
ta <- table(a)
tb <- table(b)
Function<-function(Tab1,Tab2){elements=sort(unique(c(names(ta),names(tb))))
OP=lapply(1:length(elements),FUN=function(x){a=which(elements[x]==names(Tab1))
b=which(elements[x]==names(Tab2))
if(length(a)>0&length(b)>0){Tab1[a]+Tab2[b]
}else if (length(a)>0){Tab1[a]
}else{Tab2[b]}
})
return(unlist(OP))
}
Function(ta,tb)
Best,
Heramb
On Thu, Sep 20, 2012 at 10:40 PM, arun <smartpink...@yahoo.com> wrote:
> HI Stefan,
> Thanks for the solutions.
>
> Just to add 1 more:
> f.a<-table(a); f.b<-table(b)
>
> c(f.a[!names(f.a)%in%names(f.b)],f.b[!names(f.b)%in%names(f.a)],xtabs(f.a[names(f.a)%in%names(f.b)]+f.b[names(f.b)%in%names(f.a)]~
> names(f.a[names(f.a)%in%names(f.b)])))
>
> #e i j a b d f g
> #1 1 1 3 1 3 5 5
>
> A.K.
>
>
>
> ----- Original Message -----
> From: Stefan Th. Gries <stgr...@gmail.com>
> To: mce...@lightminersystems.com
> Cc: r-help@r-project.org
> Sent: Thursday, September 20, 2012 10:57 AM
> Subject: [R] (no subject)
>
> >From my book on corpus linguistics with R:
>
> # (10) Imagine you have two vectors a and b such that
> a<-c("d", "d", "j", "f", "e", "g", "f", "f", "i", "g")
> b<-c("a", "g", "d", "f", "g", "a", "f", "a", "b", "g")
>
> # Of these vectors, you can create frequency lists by writing
> freq.list.a<-table(a); freq.list.b<-table(b)
> rm(a); rm(b)
>
> # How do you merge these two frequency lists without merging the two
> vectors first? More specifically, if I delete a and b from your
> memory,
> rm(a); rm(b)
> # how do you generate the following table only from freq.list.a and
> freq.list.b, i.e., without any reference to a and b themselves? Before
> you complain about this question as being unrealistic, consider the
> possibility that you generated the frequency lists of two corpora
> (here, a and b) that are so large that you cannot combine them into
> one (a.and.b<-c(a, b)) and generate a frequency list of that combined
> vector (table(a.and.b)) ...
> joint.freqs
> a b d e f g i j
> 3 1 3 1 5 5 1 1
>
> joint.freqs<-vector(length=length(sort(unique(c(names(freq.list.a),
> names(freq.list.b)))))) # You generate an empty vector joint.freqs (i)
> that is as long as there are different types in both a and b (but note
> that, as requested, this information is not taken from a or b, but
> from their frequency lists) ...
> names(joint.freqs)<-sort(unique(c(names(freq.list.a),
> names(freq.list.b)))) # ... and (ii) whose elements have these
> different types as names.
> joint.freqs[names(freq.list.a)]<-freq.list.a # The elements of the new
> vector joint.freqs that have the same names as the frequencies in the
> first frequency list are assigned the respective frequencies.
>
> joint.freqs[names(freq.list.b)]<-joint.freqs[names(freq.list.b)]+freq.list.b
> # The elements of the new vector joint.freqs that have the same names
> as the frequencies in the second frequency list are assigned the sum
> of the values they already have (either the ones from the first
> frequency list or just zeroes) and the respective frequencies.
> joint.freqs # look at the result
>
> # Another shorter and more elegant solution was proposed by Claire
> Crawford (but uses a function which will only be introduced later in
> the book)
> freq.list.a.b<-c(freq.list.a, freq.list.b) # first the two frequency
> lists are merged into a single vector ...
> joint.freqs<-as.table(tapply(freq.list.a.b, names(freq.list.a.b),
> sum)) # ... and then the sums of all numbers that share the same names
> are computed
> joint.freqs # look at the result
>
> # The shortest, but certainly not memory-efficient way to do this
> involves just using the frequency lists to create one big vector with
> all elements and tabulate that.
> table(c(rep(names(freq.list.a), freq.list.a), rep(names(freq.list.b),
> freq.list.b))) # kind of cheating but possible with short vectors ...
>
> HTH,
> STG
> --
> Stefan Th. Gries
> -----------------------------------------------
> University of California, Santa Barbara
> http://www.linguistics.ucsb.edu/faculty/stgries
>
> ______________________________________________
> R-help@r-project.org mailing list
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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.
>
>
> ______________________________________________
> R-help@r-project.org mailing list
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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.
>
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