How can I escape LaTeX special characters inside django templates?

Question

I have this django template which I use to generate LaTeX files

\documentclass[11pt]{report}

\begin{document}
\begin{table}
    \centering
    \begin{tabular}{lcr}
    \hline
    {% for col in head %}
        \textbf{ {{col}} }
        {% if not forloop.last %}
           &
        {% endif %}
    {% endfor %} 
    \\
    \hline
    {% for row in table %}
        {% for cell in row %}

            {% if not forloop.last %} 
               &
            {% endif %}
        {% endfor %}
        \\
    {% endfor %}
    \hline
    \end{tabular}
    \caption{Simple Phonebook}
    \label{tab:phonebook}
\end{table}

\end{document}

But my no of columns are very large so they can contain any special characters in them. I am getting error while generating pdf file.

How can I escape all the text in all columns?

Mark · Answer 1 · 2020-02-16T11:02:38.943

30

Alex's answer including suggestions in code, if you want to copy-paste:

import re

def tex_escape(text):
    """
        :param text: a plain text message
        :return: the message escaped to appear correctly in LaTeX
    """
    conv = {
        '&': r'\&',
        '%': r'\%',
        '$': r'\$',
        '#': r'\#',
        '_': r'\_',
        '{': r'\{',
        '}': r'\}',
        '~': r'\textasciitilde{}',
        '^': r'\^{}',
        '\\': r'\textbackslash{}',
        '<': r'\textless{}',
        '>': r'\textgreater{}',
    }
    regex = re.compile('|'.join(re.escape(str(key)) for key in sorted(conv.keys(), key = lambda item: - len(item))))
    return regex.sub(lambda match: conv[match.group()], text)

See Easiest way to replace a string using a dictionary of replacements? for replacement approach.

edited Feb 16 '20 at 11:02

answered Sep 16 '14 at 17:57

Mark

18,730
7
107
130

1

Thanks for the code! I think there should also be a space after `\textless` and `\textgreater`. I got "Undefined control sequence" because ` – minhle_r7 Jun 16 '17 at 10:54
Is there a reason for using `r'\textless '` instead of `r'\textless{}'` ? – Tyilo May 26 '18 at 20:44
Nah if you think its better I'll change it – Mark May 27 '18 at 08:02
2

note that the 'unicode' function has been deprecated in Python 3, use 'str' instead – Andrew Magerman Oct 24 '18 at 12:27
I think it is not necessary to sort `conv` by keys because all keys are of same length. – Mitar Jun 30 '19 at 20:48

Alex · Answer 2 · 2013-04-28T15:12:48.557

5

Something like this should do:

CHARS = {
    '&':  r'\&',
    '%':  r'\%', 
    '$':  r'\$', 
    '#':  r'\#', 
    '_':  r'\letterunderscore{}', 
    '{':  r'\letteropenbrace{}', 
    '}':  r'\letterclosebrace{}',
    '~':  r'\lettertilde{}', 
    '^':  r'\letterhat{}', 
    '\\': r'\letterbackslash{}',
}

print("".join([CHARS.get(char, char) for char in "&%$#_{}~^\\"]))

Create you own template filter to filter your variables

[edit]:

This was the special characters for ConText, for LaTex, adapt with:

\& \% \$ \# \_ \{ \} \textasciitilde{} \^{} \textbackslash{}

edited Apr 28 '13 at 15:12

answered Apr 28 '13 at 14:51

Alex

247
1
13

1

don't forget to also include r'\textgreater' r'\textless' – blueberryfields May 14 '13 at 01:55
or r'\ensuremath{<}' and r'\ensuremath{>}' – sastanin Sep 15 '14 at 10:53

How can I escape LaTeX special characters inside django templates?

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