retain - Retaining variable value in a dataframe in r -

i have dataframe in r

id subgroup first.id var 103  17     true     abc 103  17     false    xyz 103  17     false    def 103  17     false    pqr 106  16     true     abc 106  16     false    pqr 

first.id created identify first element in group(id). want create new variable should retain value in group. here, group use id variable. new dataframe should this

id subgroup first.id var condition 103  17     true     abc abc 103  17     false    xyz abc or xyz 103  17     false    def abc or xyz or def 103  17     false    pqr abc or xyz or def or pqr 106  16     true     abc abc 106  16     false    pqr abc or pqr 

df <- read.table(text="id subgroup first.id var 103  17     true     abc 103  17     false    xyz 103  17     false    def 103  17     false    pqr 106  16     true     abc 106  16     false    pqr", header=true)  library(plyr) cumpaste <- function(x, sep) {   sapply(seq_along(x), function(y,z,sep) paste(z[1:y],            collapse=sep), z=x, sep=sep) }  ddply(df, .(id), transform, condition=cumpaste(var, " or "))  #    id subgroup first.id var                condition # 1 103       17     true abc                      abc # 2 103       17    false xyz               abc or xyz # 3 103       17    false def        abc or xyz or def # 4 103       17    false pqr abc or xyz or def or pqr # 5 106       16     true abc                      abc # 6 106       16    false pqr               abc or pqr