\begin{Schunk}
\begin{Sinput}
 reslt1 <- data.frame(
    n = grep("^ar_.*\\.n$", cnames, value = TRUE), 
    s = grep("^ar_.*\\.s$", cnames, value = TRUE), 
    l = grep("^ar_.*\\.s$", cnames, value = TRUE))
 head(reslt1, 15)
\end{Sinput}
\begin{Soutput}
                 n               s               l
1     ar_physinj.n    ar_physinj.s    ar_physinj.s
2     ar_illness.n    ar_illness.s    ar_illness.s
3     ar_chronic.n    ar_chronic.s    ar_chronic.s
4         ar_job.n        ar_job.s        ar_job.s
5      ar_hunger.n     ar_hunger.s     ar_hunger.s
6         ar_STI.n        ar_STI.s        ar_STI.s
7          ar_sa.n         ar_sa.s         ar_sa.s
8         ar_UTI.n        ar_UTI.s        ar_UTI.s
9       ar_abuse.n      ar_abuse.s      ar_abuse.s
10     ar_dental.n     ar_dental.s     ar_dental.s
11    ar_drugalc.n    ar_drugalc.s    ar_drugalc.s
12    ar_suicide.n    ar_suicide.s    ar_suicide.s
13   ar_chronrun.n   ar_chronrun.s   ar_chronrun.s
14    ar_truancy.n    ar_truancy.s    ar_truancy.s
15 ar_sysinvolve.n ar_sysinvolve.s ar_sysinvolve.s
\end{Soutput}
\end{Schunk}
