ValueError in matplotlib when using horizontal span \: LaTeX

Question

See MWE below:

import matplotlib.pyplot as plt import matplotlib.offsetbox as offsetbox fig = plt.figure() ax = fig.add_subplot(111) text1 = r'$a\,=\,{}\pm{}$'.format(0.01, 0.002) # Works. text2 = r'$a\;=\,{}\pm{}$'.format(0.01, 0.002) # Works. text3 = r'$a\:=\,{}\pm{}$'.format(0.01, 0.002) # Does not work. text = text3 ob = offsetbox.AnchoredText(text, pad=1, loc=6, prop=dict(size=13)) ob.patch.set(alpha=0.85) ax.add_artist(ob) plt.show() 

While text1 and text2 , which use the intervals \, and \; , will work without problems, text3 , which uses \: (that is: a horizontal interval located between two previous versions ) with a ValueError error:

 Traceback (most recent call last): File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_gtk3agg.py", line 42, in on_draw_event self._render_figure(w, h) File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_gtk3agg.py", line 32, in _render_figure backend_agg.FigureCanvasAgg.draw(self) File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_agg.py", line 469, in draw self.figure.draw(self.renderer) File "/usr/local/lib/python2.7/dist-packages/matplotlib/artist.py", line 59, in draw_wrapper draw(artist, renderer, *args, **kwargs) File "/usr/local/lib/python2.7/dist-packages/matplotlib/figure.py", line 1085, in draw func(*args) File "/usr/local/lib/python2.7/dist-packages/matplotlib/artist.py", line 59, in draw_wrapper draw(artist, renderer, *args, **kwargs) File "/usr/local/lib/python2.7/dist-packages/matplotlib/axes/_base.py", line 2110, in draw a.draw(renderer) File "/usr/local/lib/python2.7/dist-packages/matplotlib/offsetbox.py", line 1107, in draw bbox = self.get_window_extent(renderer) File "/usr/local/lib/python2.7/dist-packages/matplotlib/offsetbox.py", line 1063, in get_window_extent w, h, xd, yd = self.get_extent(renderer) File "/usr/local/lib/python2.7/dist-packages/matplotlib/offsetbox.py", line 1014, in get_extent w, h, xd, yd = self.get_child().get_extent(renderer) File "/usr/local/lib/python2.7/dist-packages/matplotlib/offsetbox.py", line 782, in get_extent bbox, info, d = self._text._get_layout(renderer) File "/usr/local/lib/python2.7/dist-packages/matplotlib/text.py", line 320, in _get_layout ismath=ismath) File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_agg.py", line 228, in get_text_width_height_descent self.mathtext_parser.parse(s, self.dpi, prop) File "/usr/local/lib/python2.7/dist-packages/matplotlib/mathtext.py", line 3005, in parse box = self._parser.parse(s, font_output, fontsize, dpi) File "/usr/local/lib/python2.7/dist-packages/matplotlib/mathtext.py", line 2339, in parse six.text_type(err)])) ValueError: a\:=\,0.01\pm0.002 ^ Unknown symbol: \ (at char 1), (line:1, col:2) 

Why is this LaTeX space not recognized?

Answer 1

Since matplotlib uses mathtext as the default math display tool. Mathtext is a subset of regular TeX. You can use full LaTeX with:

 from matplotlib import pyplot as plt import matplotlib as mpl mpl.rcParams['text.usetex'] = True mpl.rcParams['text.latex.preamble'] = [r'\usepackage{amsmath}'] #if needed plt.plot([1,2,3]) plt.title(r"$a\:=\,{}\pm{}$".format(0.01, 0.002)) plt.show()