formatting - 格式化Sweave表，两个挑战

我在Sweave中遇到了两个格式化挑战。一是表格中文本的斜体，二是如何在表格底部添加列求和行。有关详细信息，请参见以下MWE。

\documentclass[12pt,letterpaper,oneside]{amsart}
\usepackage{graphicx}
\usepackage{longtable}
\SweaveOpts{keep.source=TRUE}        % Keeps comments in the R code.
%
\begin{document}
% \maketitle
\section*{The Challenge}
    Italicize the taxa in the following table and add a row at the bottom which gives the sum of the sites column.

<<echo=TRUE>>=
# Creating Data
taxa <- c("Arabidopsis thaliana",
    "Populus trichocarpa",
    "Brachypodium distachyon")
sites <- c(270,320,240)
data.df <- data.frame(taxa,sites)
@
~
<<label=tab1,echo=TRUE,results=tex>>=
# Creating Table
library(xtable)
data.table <- xtable(data.df,
    caption="Sweave Output")
print(data.table,
    caption.placement="top")
@

    The results should look something like table 2, which was hand coded in \LaTeX.
\begin{table}[ht]
    \caption{Manually coded \LaTeX}
    \begin{tabular}{l l r}
        \hline
          & taxa & sites \\
        \hline
        1 & \emph{Arabidopsis thaliana}     & 270 \\
        2 & \emph{Populus trichocarpa}      & 320 \\
        3 & \emph{Brachypodium distachyon}  & 240 \\
        \hline
          & Total Sites                     & 830 \\
        \hline
    \end{tabular}
\end{table}
\end{document}

最佳答案

用\emph手动添加paste，并用rbind添加新行，并将新行的名称设置为单个空格。另外，在原始数据帧创建中使用stringsAsFactors=FALSE可以将新值添加到分类单元列。

然后，使用sanitize.text.function=identity将xtable保留在\emph命令中，并将hline.after保留在所需的行中。

\documentclass[12pt,letterpaper,oneside]{amsart}
\usepackage{graphicx}
\usepackage{longtable}
\SweaveOpts{keep.source=TRUE}  % Keeps formatting of the R code.
\begin{document}
<<echo=TRUE>>=
taxa <- c("Arabidopsis thaliana",
          "Populus trichocarpa",
          "Brachypodium distachyon")
sites <- c(270,320,240)
data.df <- data.frame(taxa,sites, stringsAsFactors=FALSE)
@
~
<<label=tab2, echo=TRUE, results=tex>>=
library(xtable)
data.df$taxa <- paste("\\emph{",taxa,"}", sep="")
data.df <- rbind(data.df, ` `=c("Total Sites", sum(data.df$sites)))
data.table <- xtable(data.df,
                     caption="Sweave Output")
print(data.table,
      caption.placement="top",
      sanitize.text.function=identity,
      hline.after=c(-1,0,nrow(data.df)-1, nrow(data.df)))
@
\end{document}