Question

I’m using the GnuplotPy interface to use Gnuplot from inside of Python. I’ve found that GnuplotPy complains when I have a newline in a GnuplotPy call. For example:

import Gnuplot
gp = Gnuplot.Gnuplot(persist = 1)
gp('set title "My plot title is very long, \n so it needs two lines"')
...
gp.plot(...)

The above code throws the following error while running:

gnuplot> so it needs two lines
     ^
     line 0: invalid command

And, the above code outputs a plot that only shows the first line of the title, but the plot is otherwise correct. If I remove the \n in the gp('set title...') line, then the error goes away.

---

According to this Gnuplot tutorial, \n is indeed a valid way of doing a multi-line label in Gnuplot. For example, the tutorial suggests doing this:

set title "This is the title\n\nThis is the x2label"

Answer 1

gnuplot and python both take the 2-character sequence (\n) as a newline. What’s happening is that python is intercepting your \n and translating it to a literal newline which gnuplot chokes on. Try using a raw string:

gp(r'set title "My plot title is very long, \n so it needs two lines"')
#  ^ The leading r makes it a raw string.

This will prevent python from intercepting your newline.