[R] merge counts from table()

[Francois Pepin]

Thanks for all the replies.

The merge solution is what I was groping toward but the factor solution is much cleaner since I do know in advance what the possible categories are.

François 

On Aug 14, 2012, at 2:39 , PIKAL Petr wrote:

> Hi
> 
> If your x and y are factors it seems to be easy, just add all levels in both.
> 
> x.f<-factor(x, levels=1:5)
> y.f<-factor(y, levels=1:5)
> 
> table(x.f)+table(y.f)
> x.f
> 1 2 3 4 5 
> 1 2 2 2 1 
> 
> If you just have output from table(x) without possibility to add levels you can go with merge
> 
> 
>> mm <- merge(as.data.frame(table(x)), as.data.frame(table(y)), by.x="x", by.y="y",all=T)
>  x Freq.x Freq.y
> 1 1      1     NA
> 2 2      1      1
> 3 3      1      1
> 4 4      1      1
> 5 5     NA      1
> 
> Here you need to change NA to 0 and perform rowSums.
> 
> mm[is.na(mm)]<-0
> rowSums(mm[-1])
> [1] 1 2 2 2 1
> t(cbind(mm[,1],rowSums(mm[-1])))
>     [,1] [,2] [,3] [,4] [,5]
> [1,]    1    2    3    4    5
> [2,]    1    2    2    2    1
> 
> Regards
> Petr
> 
>> Hi everyone,
>> 
>> Is there an easy way to combine the counts from table()?
>> 
>> Let's say that I have:
>> x<-1:4
>> y<-2:5
>> 
>> I want to replicate:
>> table(c(x,y))
>> 
>> using only table(x) and table(y) as input.
>> 
>> The reason is that it's cumbersome to carry all the values around when
>> all I care about are the counts. The actual situation has about a
>> billion counts over ~150 categories.
>> 
>> I know there's got to be a number of ways of doing things (plyr comes
>> to mind), but I can't seem to find how to accomplish it.
>> 
>> Thanks,
>> 
>> François Pepin
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