Adding \mathcal to data frame - r

Question

I'm using the papaja package to make a reproducible manuscript using R and Rmarkdown. One thing I'd like to do for my tables is have symbols using mathmode. For example, I'm trying to make a column of variables that are comparisons of two z\mathcalc{M}symbols (e.g.,$\mathcal{M}_1 - \mathcal{M}_2$`, which looks like this in Rmarkdown:
However, when I try to use these symbols as cells within a data.frame, R spits out a warning:
table1 <- c("$\mathcal{M}_1 - \mathcal{M}_3$",
"$\mathcal{M}_1 - \mathcal{M}_3$",
"$\mathcal{M}_1 - \mathcal{M}_4$",
"$\mathcal{M}_1 - \mathcal{M}_5$",
"$\mathcal{M}_2 - \mathcal{M}_3$",
"$\mathcal{M}_2 - \mathcal{M}_4$",
"$\mathcal{M}_2 - \mathcal{M}_5$",
"$\mathcal{M}_3 - \mathcal{M}_4$",
"$\mathcal{M}_3 - \mathcal{M}_5$",
"$\mathcal{M}_4 - \mathcal{M}_5$")
table2 <- c(49.273540, 198.383423, 198.956909, 198.846716, 198.933951, 198.200322, 197.778849, 11.361870, 14.627681, 7.231055)
table <- data.frame(table1,table2)
Error: '\m' is an unrecognized escape in character string starting ""$\m"
From what I've found elsewhere about using mathmode in R, one solution is to use two slashes, which would look like this:
table1 <- c("$\\mathcal{M}_1 - \\mathcal{M}_3$",
"$\\mathcal{M}_1 - \\mathcal{M}_3$",
"$\\mathcal{M}_1 - \\mathcal{M}_4$",
"$\\mathcal{M}_1 - \\mathcal{M}_5$",
"$\\mathcal{M}_2 - \\mathcal{M}_3$",
"$\\mathcal{M}_2 - \\mathcal{M}_4$",
"$\\mathcal{M}_2 - \\mathcal{M}_5$",
"$\\mathcal{M}_3 - \\mathcal{M}_4$",
"$\\mathcal{M}_3 - \\mathcal{M}_5$",
"$\\mathcal{M}_4 - \\mathcal{M}_5$")
table2 <- c(49.273540, 198.383423, 198.956909, 198.846716, 198.933951, 198.200322, 197.778849, 11.361870, 14.627681, 7.231055)
table <- data.frame(table1,table2)
So far, so good. No error messages. However, when I try and format this with the papaja package into a latex table using the apa_table function, I get this:
> apa_table(table)
\begin{table}[tbp]
\begin{center}
\begin{threeparttable}
\begin{tabular}{ll}
\toprule
table1 & \multicolumn{1}{c}{table2}\\
\midrule
\$\textbackslash{}mathcal\{M\}\_1 - \textbackslash{}mathcal\{M\}\_3\$ & 49.27\\
\$\textbackslash{}mathcal\{M\}\_1 - \textbackslash{}mathcal\{M\}\_3\$ & 198.38\\
\$\textbackslash{}mathcal\{M\}\_1 - \textbackslash{}mathcal\{M\}\_4\$ & 198.96\\
\$\textbackslash{}mathcal\{M\}\_1 - \textbackslash{}mathcal\{M\}\_5\$ & 198.85\\
\$\textbackslash{}mathcal\{M\}\_2 - \textbackslash{}mathcal\{M\}\_3\$ & 198.93\\
\$\textbackslash{}mathcal\{M\}\_2 - \textbackslash{}mathcal\{M\}\_4\$ & 198.20\\
\$\textbackslash{}mathcal\{M\}\_2 - \textbackslash{}mathcal\{M\}\_5\$ & 197.78\\
\$\textbackslash{}mathcal\{M\}\_3 - \textbackslash{}mathcal\{M\}\_4\$ & 11.36\\
\$\textbackslash{}mathcal\{M\}\_3 - \textbackslash{}mathcal\{M\}\_5\$ & 14.63\\
\$\textbackslash{}mathcal\{M\}\_4 - \textbackslash{}mathcal\{M\}\_5\$ & 7.23\\
\bottomrule
\end{tabular}
\end{threeparttable}
\end{center}
\end{table}
Which doesn't produce my desired table:
So in summary, how can I get $\mathcal{M}_1 - \mathcal{M}_2$ simply into my table besides just pasting this in manually? I have to do this often so I'd like a simpler way of assigning the values.

Answer 1

apa_table escapes your strings to be literally transcribed in LaTeX. This is usually what you want but in your case you can pass escape = FALSE to apa_table.
Unfortunately the default parameter for this argument is inconsistent between different S3 methods of this generic function. This is probably a bug.