Installing pygal under Ubuntu 18.04

[ybeco]

Hi

I put "render_to_png" instead of "render_png"
I installed CairoSVG :
https://cairosvg.org/ --> pip3 install cairosvg

Output:
yonnel@yonnel-Z97X-Gaming-7:~$ pip3 install cairosvg
Collecting cairosvg
  Downloading https://files.pythonhosted.org/packages/db/8c/eb114f08b0db43ec05c946e33d1a180819f34c185f05223407ac9a6fce90/CairoSVG-2.1.3-py3-none-any.whl (101kB)
    100% |████████████████████████████████| 102kB 539kB/s 
Collecting defusedxml (from cairosvg)
  Downloading https://files.pythonhosted.org/packages/87/1c/17f3e3935a913dfe2a5ca85fa5ccbef366bfd82eb318b1f75dadbf0affca/defusedxml-0.5.0-py2.py3-none-any.whl
Collecting cairocffi (from cairosvg)
  Downloading https://files.pythonhosted.org/packages/7a/2f/78179fea3413322fd20be407897738e5569e876e7cb6e4647a79b1ffd8dd/cairocffi-0.8.1.tar.gz (79kB)
    100% |████████████████████████████████| 81kB 879kB/s 
Collecting tinycss2 (from cairosvg)
  Downloading https://files.pythonhosted.org/packages/88/95/0ec73db7fc638ec000e662936ffe1a4e1eaa22f2861c8de18b1597c42584/tinycss2-0.6.1-py2.py3-none-any.whl (61kB)
    100% |████████████████████████████████| 71kB 863kB/s 
Collecting pillow (from cairosvg)
  Downloading https://files.pythonhosted.org/packages/d1/24/f53ff6b61b3d728b90934bddb4f03f8ab584a7f49299bf3bde56e2952612/Pillow-5.2.0-cp36-cp36m-manylinux1_x86_64.whl (2.0MB)
    100% |████████████████████████████████| 2.0MB 471kB/s 
Collecting cssselect2 (from cairosvg)
  Downloading https://files.pythonhosted.org/packages/12/e2/91fcd4cd32545beec6e11628d64d3e20f11b5a95dd1ccf3216fd69f176b7/cssselect2-0.2.1-py2.py3-none-any.whl
Collecting cffi>=1.1.0 (from cairocffi->cairosvg)
  Downloading https://files.pythonhosted.org/packages/6d/c0/47db8f624f3e4e2f3f27be03a93379d1ba16a1450a7b1aacfa0366e2c0dd/cffi-1.11.5-cp36-cp36m-manylinux1_x86_64.whl (421kB)
    100% |████████████████████████████████| 430kB 837kB/s 
Collecting webencodings>=0.4 (from tinycss2->cairosvg)
  Downloading https://files.pythonhosted.org/packages/f4/24/2a3e3df732393fed8b3ebf2ec078f05546de641fe1b667ee316ec1dcf3b7/webencodings-0.5.1-py2.py3-none-any.whl
Collecting pycparser (from cffi>=1.1.0->cairocffi->cairosvg)
  Downloading https://files.pythonhosted.org/packages/8c/2d/aad7f16146f4197a11f8e91fb81df177adcc2073d36a17b1491fd09df6ed/pycparser-2.18.tar.gz (245kB)
    100% |████████████████████████████████| 256kB 880kB/s 
Building wheels for collected packages: cairocffi, pycparser
  Running setup.py bdist_wheel for cairocffi ... done
  Stored in directory: /home/yonnel/.cache/pip/wheels/1f/f5/ea/087a29f65225d037e27e329c7e7d7807cc49be81a54418e3f4
  Running setup.py bdist_wheel for pycparser ... done
  Stored in directory: /home/yonnel/.cache/pip/wheels/c0/a1/27/5ba234bd77ea5a290cbf6d675259ec52293193467a12ef1f46
Successfully built cairocffi pycparser
Installing collected packages: defusedxml, pycparser, cffi, cairocffi, webencodings, tinycss2, pillow, cssselect2, cairosvg
Successfully installed cairocffi-0.8.1 cairosvg-2.1.3 cffi-1.11.5 cssselect2-0.2.1 defusedxml-0.5.0 pillow-5.2.0 pycparser-2.18 tinycss2-0.6.1 webencodings-0.5.1

The complet scrip is:

import pygal
 
# http://blog.codeeval.com/codeevalblog/2014
# most popular coding languages according to @codeeval
# python for the win! w00t!
 
data = [
  ["Python", 30.3],
  ["Java", 22.2],
  ["C++", 13],
  ["Ruby", 10.6],
  ["Javascript", 5.2],
  ["C#", 5],
  ["C", 4.1],
  ["PHP", 3.3],
  ["Perl", 1.6],
  ["Go", 1.5],
  ["Haskell", 1.2],
  ["Scala", 1],
  ["Objective-C", 0.4],
  ["Clojure", 0.2],
  ["Bash", 0.1],
  ["Lua", 0.04],
  ["TCL", 0.03]
]
# Make a Pygal chart
pie_chart = pygal.Pie()
 
# add a title
pie_chart.title = "CodeEval Most Popular Coding Languages of 2014"
 
# add the data
for label, data_points in data:
    pie_chart.add(label, data_points)
 
# Render the chart    
pie_chart.render_to_png('foo.png')

But now I have a new error message:

Error:
Python 3.7.0b3 (default, Mar 30 2018, 04:35:22) 
[GCC 7.3.0] on linux
Type "copyright", "credits" or "license()" for more information.
>>> 
 RESTART: /media/yonnel/SSD-1T/yonnel/Dropbox/00- DIY/11- Python/02- Essais/Essais Pygal/foobarbaz.py 
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/cairosvg/surface/__init__.py", line 25, in <module>
    import cairocffi as cairo
  File "/usr/lib/python3/dist-packages/cairocffi/__init__.py", line 18, in <module>
    from ._ffi import ffi
  File "/usr/lib/python3/dist-packages/cairocffi/_ffi.py", line 2, in <module>
    import _cffi_backend
ModuleNotFoundError: No module named '_cffi_backend'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/media/yonnel/SSD-1T/yonnel/Dropbox/00- DIY/11- Python/02- Essais/Essais Pygal/foobarbaz.py", line 37, in <module>
    pie_chart.render_to_png('foo.png')
  File "/usr/lib/python3/dist-packages/pygal/graph/public.py", line 118, in render_to_png
    import cairosvg
  File "/usr/lib/python3/dist-packages/cairosvg/__init__.py", line 27, in <module>
    from . import surface
  File "/usr/lib/python3/dist-packages/cairosvg/surface/__init__.py", line 30, in <module>
    import cairo  # pycairo
  File "/usr/lib/python3/dist-packages/cairo/__init__.py", line 1, in <module>
    from ._cairo import *  # noqa: F401,F403
ModuleNotFoundError: No module named 'cairo._cairo'
>>>