lstlisting looks working great on python scripts except for some signs. From my experience the symbols "-" and "*" are replaced with something else, very similar in shape, but different. As a result the script reported into the pdf file doesn't work. That's the problem we are dealing with.
Here a simple sample code we gonna use in order to deal with this issue:
\documentclass{article}
\usepackage{listings}
\begin{document}
\lstset{language=Python}
\lstset{frame=lines}
\lstset{caption={Insert code directly in your document}}
\lstset{label={lst:code_direct}}
\lstset{basicstyle=\footnotesize}
%\lstset{keepspaces=true}
\lstset{columns=fullflexible}
\begin{lstlisting}
import numpy as np
import matplotlib.pyplot as plt
x = np.arange(-3, 3, 0.01)
y = np.sin(np.pi*x)/(np.pi*x)
plt.plot(x, y)
\end{lstlisting}
\end{document}
When I run it a pdf file is generated which looks great
import numpy as np
import matplotlib.pyplot as plt
x = np.arange(−3, 3, 0.01)
y = np.sin(np.pi∗x)/(np.pi∗x)
plt.plot(x, y)
However, if I try to copy and paste this code on a Python intepreter I realize it does not work, as "*" and "-" are replaced with something else, very similar in shape, but different. Could you help me to fix it, please?
Not totally clear to me why this happens... can you add your preamble to the code? In particular, I am wondering what encoding (inutenc) you use.
Not sure why listings behaves this way, but I found a literate option that allows specifying characters that should get replaced in the listing. In this case, I replace the minus with a minus, which seems to prevent some other code from replacing it with a different character. (I always got an equals sign.)
This works for me:
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{listings}
\begin{document}
\lstset{language=Python, literate={-}{-}1}
\lstset{frame=lines}
\lstset{caption={Insert code directly in your document}}
\lstset{label={lst:code_direct}}
\lstset{basicstyle=\footnotesize}
\lstset{keepspaces=true}
\lstset{columns=fullflexible}
\begin{lstlisting}
import numpy as np
import matplotlib.pyplot as plt
x = np.arange(-3, 3, 0.01)
y = np.sin(np.pi*x)/(np.pi*x)
plt.plot(x, y)
\end{lstlisting}
\end{document}
Inspired by this question on tex.stackexchange.com.