Output multiple objects from function R -

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i'm not sure if question exists or not. after looking around internet, can't find relates specific problem.

so, in r programming, mass output objects (specifically time series objects) data frame splitting it. before this, have been pasting duplicate concatenation commands each user , feels extremely tedious process, wondering if build function split data frame variable, apply ts() function, label object created, , output objects created.

now ideally, first thing thought of using command , apply function each split. example, below code tried (note, small example, real data frame larger this). 

#test df stackoverflow df<-data.frame(user=c(rep(1,5),rep(2,5),rep(3,5),rep(4,5))) df$values<-c(10,20,30,40,9,19,29,39,11,21,31,41,12,22,32,42,8,18,34,44)  #playing around command dd<-by(df,df$user,fun=function(x){   time = ts(x$values,freqency=2),   label = x$user[1],   label<-time,   return(label) })

the error says there's error squiggly bracket. i've looked @ ddply in 'plyr' package, couldn't working either.

any advice/help/comments appreciated, thanks.

if understood correctly want split data.frame variable , transform each portion time series object.

you can use plyr , result list (if number of data per user not equal)

require(plyr) dlply(df, .(user), function(df) ts(df$value, frequency = 12))

you can still use by if want too

by(df$value, df$user, function(x) ts(x, frequency = 12))  ## df$user: 1 ##   jan feb mar apr may ## 1  10  20  30  40   9 ## ------------------------------------------------  ## df$user: 2 ##   jan feb mar apr may ## 1  19  29  39  11  21 ## ------------------------------------------------  ## df$user: 3 ##   jan feb mar apr may ## 1  31  41  12  22  32 ## ------------------------------------------------  ## df$user: 4 ##   jan feb mar apr may ## 1  42   8  18  34  44

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