\begin{knitrout}
\definecolor{shadecolor}{rgb}{0.969, 0.969, 0.969}\color{fgcolor}\begin{kframe}
\begin{alltt}
\hlstd{df} \hlkwb{<-} \hlkwd{data.frame}\hlstd{(rost, ves)}
\hlstd{df}
\end{alltt}
\begin{verbatim}
##   rost ves
## 1  160  NA
## 2  175  70
## 3  155  48
## 4  190  85
## 5   NA  60
\end{verbatim}
\begin{alltt}
\hlstd{df[}\hlnum{3}\hlstd{,}\hlnum{1}\hlstd{]}
\end{alltt}
\begin{verbatim}
## [1] 155
\end{verbatim}
\end{kframe}
\end{knitrout}