
\subsection{Checksum: Factor, Specific, and Total Variance}
Perhaps the most basic test of a regression model is if the factor and specific variances sum to equal the total variance. Here, we
present this diagnostic as an xy-plot, with the sum of factor and specific variance on the x-axis and the total variance on the y-axis. We
expect the plotted points to line up tightly along the identity line.
\clearpage
\begin{figure}[!h]
\centering
\includegraphics{\Sexpr{image_dir}xyplotFacSpecTotVarTest.pdf}
\caption{Total Variance vs. Sum of Factor and Specific Variance, All Instruments Passing Exposure Model.}
\end{figure}
問題:
我如何處理“xyplotFacSpecTotVarTest.pdf”不存在的情況。根據表中的內容產生的文件,而表中可能有數據,也可能沒有數據。如果缺少“xyplotFacSpecTotVarTest.pdf”,最終 PDF 產生過程會出現錯誤,我該如何處理這種情況?我已經嘗試過 /IfFileExist 但它似乎不起作用..請參閱以下實現。
\IfFileExists{{image_dir}{xyplotFacSpecTotVarTest.pdf}} {
\clearpage
\begin{figure}[!h]
\centering
\includegraphics{\Sexpr{image_dir}{xyplotFacSpecTotVarTest.pdf}}
\typeout{File Exist: xyplotFacSpecTotVarTest.pdf}
\caption{Total Variance vs. Sum of Factor and Specific Variance, All Instruments Passing Exposure Model.}
\end{figure} }
{\typeout{File DOESNT Exist: xyplotFacSpecTotVarTest.pdf}}
答案1
看看標籤,我假設您使用knitr
.為什麼不讓 R 本身(默默地)確定文件是否存在?
<<chunkname,results='asis',echo=FALSE>>=
if (file.exists(file.path(image_dir, "xyplotFacSpecTotVarTest.pdf"))) {
cat("\\clearpage\n")
cat("\\begin{figure}[!h]\n")
# and so on
}
else {
cat("\\textbf{File does not exist.}\n\n")
}
@
注意results='asis'
區塊選項。每個'd 字串都將原樣cat
輸出到檔案(因此是該選項的名稱)。.tex
換句話說,每個cat
'd 字串都將是一個要編譯的 LaTeX 指令。
您甚至可以透過建立一個奇特的 R 函數(例如)來概括上述程式碼include_if_exists(filename)
,並在多個區塊中重複使用它。