pkey: In thong tin ID cua cac record bi khuyet so lieu
In gvdovandzung/thongke: What the package does (short line)

In cac gia tri cua record lien tuc, cac bien cach nhau bang "-", cach record cach nhau bang ";"

1	pkey(t1, mvar = "")

`t1`	Ten so lieu can xuat ra
`mvar`	Loi nhac hien ra truoc khi in so lieu

data(lact)
pkey(lact[1:3,c("id","ten.tat","prn.dnt")],"In ra 3 record dau tien")
##---- Should be DIRECTLY executable !! ----
##-- ==>  Define data, use random,
##--	or do  help(data=index)  for the standard data sets.

## The function is currently defined as
function(t1,mvar=""){
    suppressWarnings(str1<-paste(label(t1),sep=",",collapse="-"))
    t1$sep1<-";"
    suppressWarnings(paste("Tho^ng tin (",str1,") cu?a ddo^'i tu+o+.ng bi. khuye^'t gia' tri. ",
    mvar,": ",paste(t(t1),sep="",collapse="-"),sep=""))
  }