Matplotlib - How to add multiple lines text box when using $ sign in the line I want to display?

Question

I need to plot r squared and power law equation in two separate lines in a text box in a figure, but I can't use the '$a=3$\n$b=2$ as I already have $ sign in my code. So whenever I try to add the '& \ &' it does not work.

'y='+str(round(m,3))+'x$^{'+str(round(j,3))+'}$'

r$^{2}$=0.95

How can I display these in two lines in a box on a figure?

Thanks

Answer 1

I'm not sure what the problem is here. If you add those two stings together with a \n in the middle, it works for me:

import matplotlib.pyplot as plt

m,j=5.3421,2.6432

fig,ax = plt.subplots()

t='y='+str(round(m,3))+'x$^{'+str(round(j,3))+'}$\n r$^{2}$=0.95'
ax.text(0.5,0.5,t)

plt.show()

Alternatively, you can do this with string formatting:

t='y={:0}x$^{{{:1}}}$ \n r$^{{2}}$=0.95'.format(m,j)

Note the single braces {:0} for the format strings, and double braces {{2}} for the latex code (and therefore triple braces when you have a format string inside some latex code {{{:1}}}

Answer 2

In case the OP wanted this:

Here's the code:

#!/usr/bin/python

import matplotlib
import matplotlib.pyplot

matplotlib.rc('text', usetex=True) #use latex for text

# add amsmath to the preamble
matplotlib.rcParams['text.latex.preamble']=[r"\usepackage{amsmath}"]

# data:
m, j = 5.3421, 2.6432

# insert a multiline latex expression
matplotlib.pyplot.text(0.2,0.2,

    r'\[' # every line is a separate raw string...
    r'\begin{split}' # ...but they are all concatenated by the interpreter :-)
    r'    y      &= ' + str(round(m,3)) + 'x^{' + str(round(j,3)) + r'}\\'
    r'    r^2    &= 0.95 '
    r'\end{split}'
    r'\]',

    size=50) # make it big so we can see it

matplotlib.pyplot.savefig("test.png")