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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?

ciferkey
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2 Answers2

22

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
Paul
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    It's probably worthwhile to point out that `cStringIO.StringIO()` provides a faster, but less flexible version of the same thing, as well. http://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. – Joe Kington Mar 28 '11 at 15:22
7

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
abasar
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    I could not get my browser to render the results of this, but if I replace `f = io.BytesIO()` with `f = io.StringIO()` then everything works fine – Martin CR Oct 19 '19 at 15:26