R help - Nov 2020 - backslash in xtable (generate latex code from R)

I'd like to have $\alpha_1$ in my table, and the column name is $\beta_0$
####
library(xtable)
mytable <- data.frame(beta_0 =
c("aa","bb","cc$\\alpha_1$"))
colnames(mytable) <- "$\\beta_0$"
print(xtable(mytable), include.rownames = F, sanitize.colnames.function
identity)
####

No problem with \beta_0, but a problem with \alpha_1:

\begin{table}[ht]
\centering
\begin{tabular}{l}
  \hline
$\beta_0$ \\
  \hline
aa \\
  bb \\
  cc\$$\backslash$alpha\_1\$ \\
   \hline
\end{tabular}
\end{table}

How may I fix the $\alpha_1$? Thanks!

	[[alternative HTML version deleted]]

You could use kable() from the knitr package.

kable(mytable, format = "latex", escape = FALSE)

\begin{tabular}{l}
\hline
$\beta_0$\\
\hline
aa\\
\hline
bb\\
\hline
cc$\alpha_1$\\
\hline
\end{tabular}


ir. Thierry Onkelinx
Statisticus / Statistician

Vlaamse Overheid / Government of Flanders
INSTITUUT VOOR NATUUR- EN BOSONDERZOEK / RESEARCH INSTITUTE FOR NATURE AND
FOREST
Team Biometrie & Kwaliteitszorg / Team Biometrics & Quality Assurance
thierry.onkelinx at inbo.be
Havenlaan 88 bus 73, 1000 Brussel
www.inbo.be

///////////////////////////////////////////////////////////////////////////////////////////
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than asking him to perform a post-mortem examination: he may be able to say
what the experiment died of. ~ Sir Ronald Aylmer Fisher
The plural of anecdote is not data. ~ Roger Brinner
The combination of some data and an aching desire for an answer does not
ensure that a reasonable answer can be extracted from a given body of data.
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///////////////////////////////////////////////////////////////////////////////////////////


<https://www.inbo.be>


Op vr 6 nov. 2020 om 13:30 schreef John <miaojpm at gmail.com>:
> I'd like to have $\alpha_1$ in my table, and the column name is
$\beta_0$
> ####
> library(xtable)
> mytable <- data.frame(beta_0 =
c("aa","bb","cc$\\alpha_1$"))
> colnames(mytable) <- "$\\beta_0$"
> print(xtable(mytable), include.rownames = F, sanitize.colnames.function
> identity)
> ####
>
> No problem with \beta_0, but a problem with \alpha_1:
>
> \begin{table}[ht]
> \centering
> \begin{tabular}{l}
>   \hline
> $\beta_0$ \\
>   \hline
> aa \\
>   bb \\
>   cc\$$\backslash$alpha\_1\$ \\
>    \hline
> \end{tabular}
> \end{table}
>
> How may I fix the $\alpha_1$? Thanks!
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

Hi,

It looks like xtable is "sanitizing" special characters in the LaTeX
output by default, by adding a double backslash, so that LaTeX will process the
characters as literals, rather than specials. It is not parsing the boundary
'$' characters to define insertion of math symbols inside text mode.

You have 'sanitize.colnames.function = identity', which is why the
column name is output 'as is'.

You would seem to need to do the same thing for the text content within the
table content:
> print(xtable(mytable), include.rownames = F, 
        sanitize.colnames.function = identity, 
        sanitize.text.function = identity)
% latex table generated in R 4.0.3 by xtable 1.8-4 package
% Fri Nov  6 07:54:51 2020
\begin{table}[ht]
\centering
\begin{tabular}{l}
  \hline
$\beta_0$ \\ 
  \hline
aa \\ 
  bb \\ 
  cc$\alpha_1$ \\ 
   \hline
\end{tabular}
\end{table}


Regards,

Marc Schwartz

> On Nov 6, 2020, at 7:39 AM, John <miaojpm at gmail.com> wrote:
> 
> I'd like to have $\alpha_1$ in my table, and the column name is
$\beta_0$
> ####
> library(xtable)
> mytable <- data.frame(beta_0 =
c("aa","bb","cc$\\alpha_1$"))
> colnames(mytable) <- "$\\beta_0$"
> print(xtable(mytable), include.rownames = F, sanitize.colnames.function
> identity)
> ####
> 
> No problem with \beta_0, but a problem with \alpha_1:
> 
> \begin{table}[ht]
> \centering
> \begin{tabular}{l}
>  \hline
> $\beta_0$ \\
>  \hline
> aa \\
>  bb \\
>  cc\$$\backslash$alpha\_1\$ \\
>   \hline
> \end{tabular}
> \end{table}
> 
> How may I fix the $\alpha_1$? Thanks!