R help - Apr 2008 - Vectorize tapply(...,cumsum) output

I would like to graph cumulative counts
and use tapply(...,cumsum) to get
the cumulative counts.
For instance:
    library(lattice)
    t<-rep(1:4,each=3)    #time
    i<-rep(1:3,times=4)   #categories
    n<-rpois(length(t),t) #count
    xyplot(n ~ t,groups=i,
    type="o",key=simpleKey(as.character(1:3),x=0,y=1,lines=T))
    N<-tapply(n,t,cumsum)

Now, what is the best way to convert N
to a vector that can be plotted?
E.g.
    xyplot(N ~ t,groups=i,
    type="o",key=simpleKey(as.character(1:3),x=0,y=1,lines=T))

Or is there a better way to get cumulative graphs?

Thanks,
Gerrit.

Hi

it is a work for do.call

try

Nc<-do.call(c,N)
xyplot(Nc ~ 
t,groups=i,type="o",key=simpleKey(as.character(1:3),x=0,y=1,lines=T))

Regards
Petr
petr.pikal at precheza.cz

r-help-bounces at r-project.org napsal dne 09.04.2008 14:53:41:
> I would like to graph cumulative counts
> and use tapply(...,cumsum) to get
> the cumulative counts.
> For instance:
>     library(lattice)
>     t<-rep(1:4,each=3)    #time
>     i<-rep(1:3,times=4)   #categories
>     n<-rpois(length(t),t) #count
>     xyplot(n ~ t,groups=i,
>     type="o",key=simpleKey(as.character(1:3),x=0,y=1,lines=T))
>     N<-tapply(n,t,cumsum)
> 
> Now, what is the best way to convert N
> to a vector that can be plotted?
> E.g.
>     xyplot(N ~ t,groups=i,
>     type="o",key=simpleKey(as.character(1:3),x=0,y=1,lines=T))
> 
> Or is there a better way to get cumulative graphs?
> 
> Thanks,
> Gerrit.
> 
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