How to highlight numbers only outside a string in lstlisting?

Question

I have some source code in Python and I would like to highlight numbers, but only if the number is part of an operation or in a declaration, that is, if I name a variable variable1 for example, I don't want the number to be coloured. To achieve that, here is the code I have written:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage[spanish]{babel}
\usepackage{listings,lstautogobble} %Código en latex
\usepackage{xcolor}

\definecolor{codegreen}{rgb}{0.04314,0.6745,0.07843}
\definecolor{codegray}{rgb}{0.7059,0.6863,0.702}
\definecolor{codered}{rgb}{0.5373,0.02745,0.06275}
\definecolor{codeblue}{rgb}{0.071,0.0258,0.9882}
\definecolor{codepurple}{rgb}{0.6,0.02745,0.5961}
\definecolor{backcolour}{rgb}{0.95,0.95,0.92}

\lstdefinestyle{mystyle}{
    commentstyle=\color{codegray},
    classoffset=1, % starting new class
    otherkeywords={range, len},
    keywordstyle=\color{codepurple},
    classoffset = 2
    morekeywords = {print}
    keywordstyle=\color{codered},
    classoffset = 0,    
    keywordstyle=\color{codeblue},
    stringstyle=\color{codegreen},
    basicstyle=\ttfamily,
    breaklines=true,                 
    showspaces=false,                
    showstringspaces=false,
    autogobble=true
}

\lstset{literate=
  {0}{{{\color{codered}0}}}1 {1}{{{\color{codered}1}}}1 
  {2}{{{\color{codered}2}}}1 {3}{{{\color{codered}3}}}1 
  {4}{{{\color{codered}4}}}1 {5}{{{\color{codered}5}}}1 
  {6}{{{\color{codered}6}}}1 {7}{{{\color{codered}7}}}1 
  {8}{{{\color{codered}8}}}1 {9}{{{\color{codered}9}}}1 
  {á}{{\'a}}1 {é}{{\'e}}1 {í}{{\'i}}1 {ó}{{\'o}}1 {ú}{{\'u}}1
  {Á}{{\'A}}1 {É}{{\'E}}1 {Í}{{\'I}}1 {Ó}{{\'O}}1 {Ú}{{\'U}}1
  {à}{{\`a}}1 {è}{{\`e}}1 {ì}{{\`i}}1 {ò}{{\`o}}1 {ù}{{\`u}}1
  {À}{{\`A}}1 {È}{{\'E}}1 {Ì}{{\`I}}1 {Ò}{{\`O}}1 {Ù}{{\`U}}1
  {ä}{{\"a}}1 {ë}{{\"e}}1 {ï}{{\"i}}1 {ö}{{\"o}}1 {ü}{{\"u}}1
  {Ä}{{\"A}}1 {Ë}{{\"E}}1 {Ï}{{\"I}}1 {Ö}{{\"O}}1 {Ü}{{\"U}}1
  {â}{{\^a}}1 {ê}{{\^e}}1 {î}{{\^i}}1 {ô}{{\^o}}1 {û}{{\^u}}1
  {Â}{{\^A}}1 {Ê}{{\^E}}1 {Î}{{\^I}}1 {Ô}{{\^O}}1 {Û}{{\^U}}1
  {Ã}{{\~A}}1 {ã}{{\~a}}1 {Õ}{{\~O}}1 {õ}{{\~o}}1
  {œ}{{\oe}}1 {Œ}{{\OE}}1 {æ}{{\ae}}1 {Æ}{{\AE}}1 {ß}{{\ss}}1
  {ű}{{\H{u}}}1 {Ű}{{\H{U}}}1 {ő}{{\H{o}}}1 {Ő}{{\H{O}}}1
  {ç}{{\c c}}1 {Ç}{{\c C}}1 {ø}{{\o}}1 {å}{{\r a}}1 {Å}{{\r A}}1
  {€}{{\euro}}1 {£}{{\pounds}}1 {«}{{\guillemotleft}}1
  {»}{{\guillemotright}}1 {ñ}{{\~n}}1 {Ñ}{{\~N}}1 {¿}{{?`}}1
  {º}{{\textordmasculine}}1 
} 

\lstset{style=mystyle}
\title{Foo}

\begin{document}

\maketitle

\begin{lstlisting}[language=Python]
       def extract_mfcc(audio,rate,winstep_nuevo):
        '''Cálculo de los coeficientes MFCC y de su primera y segunda derivada'''

        #Ventana de 20 ms, solapamiento de 10 ms, 22 coeficientes y 2048 puntos para la fft.
        #Nº de filas=nº de tramas. nº de columnas= nº de coeficientes
        mfcc_c= mfcc.mfcc(audio,rate,winlen=0.020,winstep=winstep_nuevo,numcep=22,nfft=2048,winfunc=np.hamming)    
        #Cálculo de la primera derivada de los coeficientes
        delta=librosa.feature.delta(mfcc_c,order=1)
        #Cáclulo de la segunda derivada de los coeficientes
        delta2=librosa.feature.delta(mfcc_c,order=2) 
        return  mfcc_c,delta,delta2
    \end{lstlisting}


\end{document}

But with this configuration numbers are coloured wherever they are, even in comments, as it is shown in this image:

To avoid that, I saw that writing *{0}{{{\color{codered}0}}}1 instead of {0}{{{\color{codered}0}}}1 would solve the problem. The following image shows the result for that change:

Nevertheless, although it solves the numbers issue, the problem that arises now is that if I write a special character, for example á or º in a comment, latex doesn't recognise it, and I don't know how to solve this problem and colour the numbers correctly at the same time.

Thank you for your answers.

Answer 1

You can use package minted. You have to install pygments (can easily be installed in linux by sudo apt-get install python-pygments or pip install pygments) and use -shell-escape flag in the command. eg. If you are using pdflatex, your regular command is pdflatex <filename>. It should now be pdflatex -shell-escape <filename>. See the following MWE.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage[spanish]{babel}
\usepackage{minted} %Código en latex
\usemintedstyle{vim}
\usepackage{xcolor}
\title{Foo}
\author{Josemi}

\begin{document}
    \maketitle
\begin{minted}[linenos,breaklines]{python}
       def extract_mfcc(audio,rate,winstep_nuevo):
       '''Cálculo de los coeficientes MFCC y de su primera y segunda derivada'''

       #Ventana de 20 ms, solapamiento de 10 ms, 22 coeficientes y 2048 puntos para la fft.
       #Nº de filas=nº de tramas. nº de columnas= nº de coeficientes
       mfcc_c= mfcc.mfcc(audio,rate,winlen=0.020, winstep=winstep_nuevo,numcep=22,nfft=2048,winfunc=np.hamming)    
       #Cálculo de la primera derivada de los coeficientes
       delta=librosa.feature.delta(mfcc_c,order=1)
       #Cáclulo de la segunda derivada de los coeficientes
       delta2=librosa.feature.delta(mfcc_c,order=2) 
       return  mfcc_c,delta,delta2
\end{minted}
\end{document}

This gave me the following output.

PS - You can remove optional argument [linenos] or [breaklines] if you don't need those functions. I've added them because I like them ;)