I'd like to use Matplotlib and pyplot to generate an svg image to be used in a Django framework. as of now I have it generating image files that are link to by the page, but is there a way to directly get with the svg image as a unicode string without having to write to the file system?
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3 Answers
Try using StringIO to avoid writing any file-like object to disk.
import matplotlib.pyplot as plt import StringIO from matplotlib import numpy as np x = np.arange(0,np.pi*3,.1) y = np.sin(x) fig = plt.figure() plt.plot(x,y) imgdata = StringIO.StringIO() fig.savefig(imgdata, format='svg') imgdata.seek(0) # rewind the data svg_dta = imgdata.buf # this is svg data file('test.htm', 'w').write(svg_dta) # test it 
1 Comment
Joe Kington
It's probably worthwhile to point out that
cStringIO.StringIO() provides a faster, but less flexible version of the same thing, as well. docs.python.org/library/stringio.html#module-cStringIO If the OP is actually going to use it in production code, it may make a difference (or not!). Regardless, a StringIO file-like object is definitely the way to go.Here is python3 version
import matplotlib.pyplot as plt import numpy as np import io f = io.BytesIO() a = np.random.rand(10) plt.bar(range(len(a)), a) plt.savefig(f, format = "svg") print(f.getvalue()) # svg string 
Based on abasar's answer, I propose the following snippet:
from io import StringIO import matplotlib.pyplot as plt def plot_to_svg() -> str: """ Saves the last plot made using ``matplotlib.pyplot`` to a SVG string. Returns: The corresponding SVG string. """ s = StringIO() plt.savefig(s, format="svg") plt.close() # https://stackoverflow.com/a/18718162/14851404 return s.getvalue() a = [10, 20, 5] plt.bar(range(len(a)), a) svg = plot_to_svg() print(svg) 