[Tex/LaTex] listings with R: keywords in variable names are highlighted when using underscores

listingsr

When using language=R as a lstlistings style, if a variable name contains a keyword surrounded by underscores it will be highlighted. See the image and code example below. What can I do to prevent this from happening?

Other languages like Java seem to work fine, as do variable names without underscores. I tried alsoletter=_ but that doesn't change anything.

\documentclass{article}
\usepackage{listings}
\usepackage{color}

\lstdefinestyle{generalStyle} {
    frame=single,
    keywordstyle=\color{blue}\bfseries,
    stringstyle=\color{magenta}
}

\lstdefinestyle{JavaStyle} {
    language=Java, 
    style=generalStyle
}

\lstdefinestyle{RStyle} {
    language=R,
    style=generalStyle  
}

\begin{document}

    Java
    \begin{lstlisting}[style=JavaStyle]
        some_String_int_thing = "Somestring"
    \end{lstlisting}

    R
    \begin{lstlisting}[style=RStyle]
        some_data_csv_thing = 'Somestring'
    \end{lstlisting}

\end{document}

Best Answer

R syntax highlighting is defined in lstlang3.sty. The definition for R in that file contains the following:

 otherkeywords={!,!=,~,$,*,\&,\%/\%,\%*\%,\%\%,<-,<<-,_,/},
 alsoother={._$},

If you want to remove the special treatment of _ then add something like this to your own definition of RStyle

 otherkeywords={!,!=,~,$,*,\&,\%/\%,\%*\%,\%\%,<-,<<-,/},
 alsoother={.$},

(that is, remove the underscores). Besure to get the commas right at the end of the lines.

Related Solutions

[Tex/LaTex] Latex listings R: need mono-spaced font with bold keywords and correct caret (^)

instead of courier use

\documentclass{article}
\usepackage[T1]{fontenc}     
\usepackage{beramono}     
...

[Tex/LaTex] Inconsistent output for R language operators when using listings package

A possible manual approach is with the use of moredelim=**[is][\bfseries]{@}{@},

Can I also suggest a style? Below I have defined \lstdefinelanguage customRthree in conjunction with package courier. You can also try beramono. See for instance, Latex listings R: need mono-spaced font with bold keywords and correct caret (^).

\lstdefinelanguage{customRthree}{
    keywords={t},
    otherkeywords={<<-,\%*\%},    %% cannot add <-
    keywordstyle=\bfseries,
    moredelim=**[is][\bfseries]{@}{@}, % every character inside @ @ will be in bold face
    basicstyle=\ttfamily,
    commentstyle=\textsl,
}

Code

\documentclass[preview,border=5,convert]{standalone}

\usepackage{courier}

\usepackage{listings}           
\lstdefinelanguage{customR}{    % defined a new R entry
  keywords={t},
  otherkeywords={<<-,\%*\%},    %% cannot add <-
  keywordstyle=\bfseries,
  moredelim=**[is][\bfseries]{@}{@},
}
\lstdefinelanguage{customRtwo}{
  otherkeywords={<-,<<-,\%*\%},  %% cannot add <-
  keywordstyle=\bfseries,
  moredelim=**[is][\bfseries]{@}{@},
}

\lstdefinelanguage{customRthree}{
    keywords={t,R},
    otherkeywords={<<-,\%*\%},    %% cannot add <-
    keywordstyle=\bfseries,
    moredelim=**[is][\bfseries]{@}{@},
    basicstyle=\ttfamily,
    commentstyle=\textsl,
}

\begin{document} 

\lstset{language=R,caption={Standard R}}
\begin{lstlisting}[frame=tb]
    S <- H %*% t(pprd) %*% t(H) + R
    xest <<- xprd + kalmangain %*% (z - H %*% xprd)
}
\end{lstlisting}

\lstset{language=customR,caption={Custom R}}
\begin{lstlisting}[frame=tb]
    S @<-@ H %*% t(pprd) %*% t(H) + R
    xest @<<-@ xprd + kalmangain %*% (z - H %*% xprd)
}
\end{lstlisting}

\lstset{language=customRtwo,caption={Custom R (alt.)}}
\begin{lstlisting}[frame=tb]
    S <- H %*% t(pprd) %*% t(H) + R
    xest @<@<- xprd + kalmangain %*% (z - H %*% xprd)
}
\end{lstlisting}

\begin{lstlisting}[frame=tb,language=customRthree,caption={Custom R 3}]
    S @<-@ H %*% t(pprd) %*% t(H) + R
    xest @<<-@ xprd + kalmangain %*% (z - H %*% xprd)
}
\end{lstlisting}

\end{document}

Output

enter image description here