Python 2.7: Unable to import matplotlib.pyplot

Question

When I tried to

import matplotlib.pyplot as plt

I was given the following error:

runfile('/Users/Zhengnan/Documents/Python/PS 2/230I_PS_2.py', wdir='/Users/Zhengnan/Documents/Python/PS 2')
Traceback (most recent call last):

File "<ipython-input-2-9001323bba15>", line 1, in <module>
runfile('/Users/Zhengnan/Documents/Python/PS 2/230I_PS_2.py', wdir='/Users/Zhengnan/Documents/Python/PS 2')

File "/Users/Zhengnan/anaconda/lib/python2.7/site-packages/spyderlib/widgets/externalshell/sitecustomize.py", line 685, in runfile
execfile(filename, namespace)

File "/Users/Zhengnan/anaconda/lib/python2.7/site-packages/spyderlib/widgets/externalshell/sitecustomize.py", line 78, in execfile
builtins.execfile(filename, *where)

File "/Users/Zhengnan/Documents/Python/PS 2/230I_PS_2.py", line 4, in <module>
import matplotlib.pyplot as plt

File "/Users/Zhengnan/anaconda/lib/python2.7/site-packages/matplotlib/pyplot.py", line 27, in <module>
import matplotlib.colorbar

File "/Users/Zhengnan/anaconda/lib/python2.7/site-packages/matplotlib/colorbar.py", line 34, in <module>
import matplotlib.collections as collections

File "/Users/Zhengnan/anaconda/lib/python2.7/site-packages/matplotlib/collections.py", line 27, in <module>
import matplotlib.backend_bases as backend_bases

File "/Users/Zhengnan/anaconda/lib/python2.7/site-packages/matplotlib/backend_bases.py", line 56, in <module>
import matplotlib.textpath as textpath

File "/Users/Zhengnan/anaconda/lib/python2.7/site-packages/matplotlib/textpath.py", line 22, in <module>
from matplotlib.mathtext import MathTextParser

File "/Users/Zhengnan/anaconda/lib/python2.7/site-packages/matplotlib/mathtext.py", line 63, in <module>
import matplotlib._png as _png

ImportError: dlopen(/Users/Zhengnan/anaconda/lib/python2.7/site-packages/matplotlib/_png.so, 2): Library not loaded: @loader_path/../../../libpng15.15.dylib
Referenced from: /Users/Zhengnan/anaconda/lib/python2.7/site-packages/matplotlib/_png.so
Reason: image not found

Can anyone please help me? I'm a newbie and not really familiar with paths. A step-by-step instruction would be greatly appreciated. Thanks in advance.

BTW, I'm using spyder as an IDE.

Answer 1

It's likely your library path is not set up correctly, and doesn't point to wherever the file libpng15.15.dylib is located.

Since this file should probably come with the anaconda installation (provided this is how you have installed Python and matplotlib), check if you can find this file in /Users/Zhangnan/anaconda/lib/.

If you find that file there, set your LD_LIBRARY_PATH:

export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:/Users/Zhangnan/anaconda/lib/

You may also want to add that line to your ${HOME}/.bashrc file.

Answer 2

I use Kali Linux,I use: pip install matplotlib

Answer 3

as presented here: https://askubuntu.com/questions/636937/python-2-7-matplotlib-provides-errorpyplot

this command will fix it: conda install matplotlib

and indeed it helped me.