Prevent mocked definition from bleeding over to external library in python - python

Suppose I have some third-party code main.py:
import matplotlib.pyplot as plt
import tkinter
tk = tkinter.Tk()
fig = plt.figure()
ax = plt.gca()
ax.plot([1,2,3])
plt.savefig('test.png')
Suppose that, in order to test this code, I need to creat a mock Tk class and replace the definition in main with it in a file called mock_main.py:
import tkinter
class Tk:
pass
tkinter.Tk = Tk
import main
Now, if I run python mock_main.py, I get an error:
Traceback (most recent call last):
File "C:\Users\user\desktop\temp\compare_mpl_backends\mock_main.py", line 8, in <module>
import main
File "C:\Users\user\desktop\temp\compare_mpl_backends\main.py", line 6, in <module>
fig = plt.figure()
File "C:\Users\user\Miniconda3\envs\temp\lib\site-packages\matplotlib\pyplot.py", line 787, in figure
manager = new_figure_manager(
File "C:\Users\user\Miniconda3\envs\temp\lib\site-packages\matplotlib\pyplot.py", line 306, in new_figure_manager
return _backend_mod.new_figure_manager(*args, **kwargs)
File "C:\Users\user\Miniconda3\envs\temp\lib\site-packages\matplotlib\backend_bases.py", line 3494, in new_figure_manager
return cls.new_figure_manager_given_figure(num, fig)
File "C:\Users\user\Miniconda3\envs\temp\lib\site-packages\matplotlib\backends\_backend_tk.py", line 925, in new_figure_manager_given_figure
window = tk.Tk(className="matplotlib")
TypeError: Tk() takes no arguments
I understand why this error occurs. matplotlib also depends on tkinter.Tk, so when I override it in mock_main.py, it basically breaks the matplotlib code.
I want to leave matplotlib alone, namely allowing it to use the true definition of Tk. However, for the third party code main.py, I want to use my (mock) definition.
Is there any elegant way to achieve this in python without modifying the contents of main.py?

Related

Not able to import matplotlib in Google Flexible App engine with flask and python 3.6 [duplicate]

I am trying to use networkx with Python. When I run this program it get this error. Is there anything missing?
#!/usr/bin/env python
import networkx as nx
import matplotlib
import matplotlib.pyplot
import matplotlib.pyplot as plt
G=nx.Graph()
G.add_node(1)
G.add_nodes_from([2,3,4,5,6,7,8,9,10])
#nx.draw_graphviz(G)
#nx_write_dot(G, 'node.png')
nx.draw(G)
plt.savefig("/var/www/node.png")
Traceback (most recent call last):
File "graph.py", line 13, in <module>
nx.draw(G)
File "/usr/lib/pymodules/python2.5/networkx/drawing/nx_pylab.py", line 124, in draw
cf=pylab.gcf()
File "/usr/lib/pymodules/python2.5/matplotlib/pyplot.py", line 276, in gcf
return figure()
File "/usr/lib/pymodules/python2.5/matplotlib/pyplot.py", line 254, in figure
**kwargs)
File "/usr/lib/pymodules/python2.5/matplotlib/backends/backend_tkagg.py", line 90, in new_figure_manager
window = Tk.Tk()
File "/usr/lib/python2.5/lib-tk/Tkinter.py", line 1650, in __init__
self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: no display name and no $DISPLAY environment variable
I get a different error now:
#!/usr/bin/env python
import networkx as nx
import matplotlib
import matplotlib.pyplot
import matplotlib.pyplot as plt
matplotlib.use('Agg')
G=nx.Graph()
G.add_node(1)
G.add_nodes_from([2,3,4,5,6,7,8,9,10])
#nx.draw_graphviz(G)
#nx_write_dot(G, 'node.png')
nx.draw(G)
plt.savefig("/var/www/node.png")
/usr/lib/pymodules/python2.5/matplotlib/__init__.py:835: UserWarning: This call to matplotlib.use() has no effect
because the the backend has already been chosen;
matplotlib.use() must be called *before* pylab, matplotlib.pyplot,
or matplotlib.backends is imported for the first time.
if warn: warnings.warn(_use_error_msg)
Traceback (most recent call last):
File "graph.py", line 15, in <module>
nx.draw(G)
File "/usr/lib/python2.5/site-packages/networkx-1.2.dev-py2.5.egg/networkx/drawing/nx_pylab.py", line 124, in draw
cf=pylab.gcf()
File "/usr/lib/pymodules/python2.5/matplotlib/pyplot.py", line 276, in gcf
return figure()
File "/usr/lib/pymodules/python2.5/matplotlib/pyplot.py", line 254, in figure
**kwargs)
File "/usr/lib/pymodules/python2.5/matplotlib/backends/backend_tkagg.py", line 90, in new_figure_manager
window = Tk.Tk()
File "/usr/lib/python2.5/lib-tk/Tkinter.py", line 1650, in __init__
self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: no display name and no $DISPLAY environment variable
I get a different error now:
#!/usr/bin/env python
import networkx as nx
import matplotlib
import matplotlib.pyplot
import matplotlib.pyplot as plt
matplotlib.use('Agg')
G=nx.Graph()
G.add_node(1)
G.add_nodes_from([2,3,4,5,6,7,8,9,10])
#nx.draw_graphviz(G)
#nx_write_dot(G, 'node.png')
nx.draw(G)
plt.savefig("/var/www/node.png")
/usr/lib/pymodules/python2.5/matplotlib/__init__.py:835: UserWarning: This call to matplotlib.use() has no effect
because the the backend has already been chosen;
matplotlib.use() must be called *before* pylab, matplotlib.pyplot,
or matplotlib.backends is imported for the first time.
if warn: warnings.warn(_use_error_msg)
Traceback (most recent call last):
File "graph.py", line 15, in <module>
nx.draw(G)
File "/usr/lib/python2.5/site-packages/networkx-1.2.dev-py2.5.egg/networkx/drawing/nx_pylab.py", line 124, in draw
cf=pylab.gcf()
File "/usr/lib/pymodules/python2.5/matplotlib/pyplot.py", line 276, in gcf
return figure()
File "/usr/lib/pymodules/python2.5/matplotlib/pyplot.py", line 254, in figure
**kwargs)
File "/usr/lib/pymodules/python2.5/matplotlib/backends/backend_tkagg.py", line 90, in new_figure_manager
window = Tk.Tk()
File "/usr/lib/python2.5/lib-tk/Tkinter.py", line 1650, in __init__
self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: no display name and no $DISPLAY environment variable

The main problem is that (on your system) matplotlib chooses an x-using backend by default. I just had the same problem on one of my servers. The solution for me was to add the following code in a place that gets read before any other pylab/matplotlib/pyplot import:
import matplotlib
# Force matplotlib to not use any Xwindows backend.
matplotlib.use('Agg')
The alternative is to set it in your .matplotlibrc

Just as a complement of Reinout's answer.
The permanent way to solve this kind of problem is to edit .matplotlibrc file. Find it via
>>> import matplotlib>>> matplotlib.matplotlib_fname()
# This is the file location in Ubuntu
'/etc/matplotlibrc'
Then modify the backend in that file to backend : Agg. That is it.

The clean answer is to take a little bit of time correctly prepare your execution environment.
The first technique you have to prepare your execution environment is to use a matplotlibrc file, as wisely recommended by Chris Q., setting
backend : Agg
in that file. You can even control — with no code changes — how and where matplotlib looks for and finds the matplotlibrc file.
The second technique you have to prepare your execution environment is to use the MPLBACKEND environment variable (and inform your users to make use of it):
export MPLBACKEND="agg"
python <program_using_matplotlib.py>
This is handy because you don't even have to provide another file on disk to make this work. I have employed this approach with, for example, testing in continuous integration, and running on remote machines that do not have displays.
Hard-coding your matplotlib backend to "Agg" in your Python code is like bashing a square peg into a round hole with a big hammer, when, instead, you could have just told matplotlib it needs to be a square hole.

I got the error while using matplotlib through Spark. matplotlib.use('Agg') doesn't work for me. In the end, the following code works for me. More here
import matplotlib.pyplot as plt.
plt.switch_backend('agg')

I will just repeat what #Ivo Bosticky said which can be overlooked. Put these lines at the VERY start of the py file.
import matplotlib
matplotlib.use('Agg')
Or one would get error
*/usr/lib/pymodules/python2.7/matplotlib/__init__.py:923: UserWarning: This call to matplotlib.use() has no effect
because the the backend has already been chosen;
matplotlib.use() must be called *before* pylab, matplotlib.pyplot,*
This will resolve all Display issue

I found this snippet to work well when switching between X and no-X environments.
import os
import matplotlib as mpl
if os.environ.get('DISPLAY','') == '':
print('no display found. Using non-interactive Agg backend')
mpl.use('Agg')
import matplotlib.pyplot as plt

When signing into the server to execute the code
use this instead:
ssh -X username#servername
the -X will get rid of the no display name and no $DISPLAY environment variable
error
:)

import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
It works for me.

What system are you on? It looks like you have a system with X11, but the DISPLAY environment variable was not properly set. Try executing the following command and then rerunning your program:
export DISPLAY=localhost:0

One other thing to check is whether your current user is authorised to connect to the X display. In my case, root was not allowed to do that and matplotlib was complaining with the same error.
user#debian:~$ xauth list
debian/unix:10 MIT-MAGIC-COOKIE-1 ae921efd0026c6fc9d62a8963acdcca0
root#debian:~# xauth add debian/unix:10 MIT-MAGIC-COOKIE-1 ae921efd0026c6fc9d62a8963acdcca0
root#debian:~# xterm
source: http://www.debian-administration.org/articles/494 https://debian-administration.org/article/494/Getting_X11_forwarding_through_ssh_working_after_running_su

To make sure your code is portable across Windows, Linux and OSX and for systems with and without displays, I would suggest following snippet:
import matplotlib
import os
# must be before importing matplotlib.pyplot or pylab!
if os.name == 'posix' and "DISPLAY" not in os.environ:
matplotlib.use('Agg')
# now import other things from matplotlib
import matplotlib.pyplot as plt
Credit: https://stackoverflow.com/a/45756291/207661

For Google Cloud Machine Learning Engine:
import matplotlib as mpl
mpl.use('Agg')
from matplotlib.backends.backend_pdf import PdfPages
And then to print to file:
#PDF build and save
def multi_page(filename, figs=None, dpi=200):
pp = PdfPages(filename)
if figs is None:
figs = [mpl.pyplot.figure(n) for n in mpl.pyplot.get_fignums()]
for fig in figs:
fig.savefig(pp, format='pdf', bbox_inches='tight', fig_size=(10, 8))
pp.close()
and to create the PDF:
multi_page(report_name)

import matplotlib
matplotlib.use('Agg')
worked for me as long as I was calling the plotting functions/code directly. But if you are using
from joblib import Parallel, delayed
Parallel and delayed modules for parallelizing your code then you need to add
matplotlib.rcParams.update({'backend': 'Agg'})
line inside your function in order for agg backend to work.

pyplot: no display name and no $DISPLAY environment variable [duplicate]

I am trying to use networkx with Python. When I run this program it get this error. Is there anything missing?
#!/usr/bin/env python
import networkx as nx
import matplotlib
import matplotlib.pyplot
import matplotlib.pyplot as plt
G=nx.Graph()
G.add_node(1)
G.add_nodes_from([2,3,4,5,6,7,8,9,10])
#nx.draw_graphviz(G)
#nx_write_dot(G, 'node.png')
nx.draw(G)
plt.savefig("/var/www/node.png")
Traceback (most recent call last):
File "graph.py", line 13, in <module>
nx.draw(G)
File "/usr/lib/pymodules/python2.5/networkx/drawing/nx_pylab.py", line 124, in draw
cf=pylab.gcf()
File "/usr/lib/pymodules/python2.5/matplotlib/pyplot.py", line 276, in gcf
return figure()
File "/usr/lib/pymodules/python2.5/matplotlib/pyplot.py", line 254, in figure
**kwargs)
File "/usr/lib/pymodules/python2.5/matplotlib/backends/backend_tkagg.py", line 90, in new_figure_manager
window = Tk.Tk()
File "/usr/lib/python2.5/lib-tk/Tkinter.py", line 1650, in __init__
self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: no display name and no $DISPLAY environment variable
I get a different error now:
#!/usr/bin/env python
import networkx as nx
import matplotlib
import matplotlib.pyplot
import matplotlib.pyplot as plt
matplotlib.use('Agg')
G=nx.Graph()
G.add_node(1)
G.add_nodes_from([2,3,4,5,6,7,8,9,10])
#nx.draw_graphviz(G)
#nx_write_dot(G, 'node.png')
nx.draw(G)
plt.savefig("/var/www/node.png")
/usr/lib/pymodules/python2.5/matplotlib/__init__.py:835: UserWarning: This call to matplotlib.use() has no effect
because the the backend has already been chosen;
matplotlib.use() must be called *before* pylab, matplotlib.pyplot,
or matplotlib.backends is imported for the first time.
if warn: warnings.warn(_use_error_msg)
Traceback (most recent call last):
File "graph.py", line 15, in <module>
nx.draw(G)
File "/usr/lib/python2.5/site-packages/networkx-1.2.dev-py2.5.egg/networkx/drawing/nx_pylab.py", line 124, in draw
cf=pylab.gcf()
File "/usr/lib/pymodules/python2.5/matplotlib/pyplot.py", line 276, in gcf
return figure()
File "/usr/lib/pymodules/python2.5/matplotlib/pyplot.py", line 254, in figure
**kwargs)
File "/usr/lib/pymodules/python2.5/matplotlib/backends/backend_tkagg.py", line 90, in new_figure_manager
window = Tk.Tk()
File "/usr/lib/python2.5/lib-tk/Tkinter.py", line 1650, in __init__
self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: no display name and no $DISPLAY environment variable
I get a different error now:
#!/usr/bin/env python
import networkx as nx
import matplotlib
import matplotlib.pyplot
import matplotlib.pyplot as plt
matplotlib.use('Agg')
G=nx.Graph()
G.add_node(1)
G.add_nodes_from([2,3,4,5,6,7,8,9,10])
#nx.draw_graphviz(G)
#nx_write_dot(G, 'node.png')
nx.draw(G)
plt.savefig("/var/www/node.png")
/usr/lib/pymodules/python2.5/matplotlib/__init__.py:835: UserWarning: This call to matplotlib.use() has no effect
because the the backend has already been chosen;
matplotlib.use() must be called *before* pylab, matplotlib.pyplot,
or matplotlib.backends is imported for the first time.
if warn: warnings.warn(_use_error_msg)
Traceback (most recent call last):
File "graph.py", line 15, in <module>
nx.draw(G)
File "/usr/lib/python2.5/site-packages/networkx-1.2.dev-py2.5.egg/networkx/drawing/nx_pylab.py", line 124, in draw
cf=pylab.gcf()
File "/usr/lib/pymodules/python2.5/matplotlib/pyplot.py", line 276, in gcf
return figure()
File "/usr/lib/pymodules/python2.5/matplotlib/pyplot.py", line 254, in figure
**kwargs)
File "/usr/lib/pymodules/python2.5/matplotlib/backends/backend_tkagg.py", line 90, in new_figure_manager
window = Tk.Tk()
File "/usr/lib/python2.5/lib-tk/Tkinter.py", line 1650, in __init__
self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: no display name and no $DISPLAY environment variable

The main problem is that (on your system) matplotlib chooses an x-using backend by default. I just had the same problem on one of my servers. The solution for me was to add the following code in a place that gets read before any other pylab/matplotlib/pyplot import:
import matplotlib
# Force matplotlib to not use any Xwindows backend.
matplotlib.use('Agg')
The alternative is to set it in your .matplotlibrc

Just as a complement of Reinout's answer.
The permanent way to solve this kind of problem is to edit .matplotlibrc file. Find it via
>>> import matplotlib>>> matplotlib.matplotlib_fname()
# This is the file location in Ubuntu
'/etc/matplotlibrc'
Then modify the backend in that file to backend : Agg. That is it.

The clean answer is to take a little bit of time correctly prepare your execution environment.
The first technique you have to prepare your execution environment is to use a matplotlibrc file, as wisely recommended by Chris Q., setting
backend : Agg
in that file. You can even control — with no code changes — how and where matplotlib looks for and finds the matplotlibrc file.
The second technique you have to prepare your execution environment is to use the MPLBACKEND environment variable (and inform your users to make use of it):
export MPLBACKEND="agg"
python <program_using_matplotlib.py>
This is handy because you don't even have to provide another file on disk to make this work. I have employed this approach with, for example, testing in continuous integration, and running on remote machines that do not have displays.
Hard-coding your matplotlib backend to "Agg" in your Python code is like bashing a square peg into a round hole with a big hammer, when, instead, you could have just told matplotlib it needs to be a square hole.

I got the error while using matplotlib through Spark. matplotlib.use('Agg') doesn't work for me. In the end, the following code works for me. More here
import matplotlib.pyplot as plt.
plt.switch_backend('agg')

I will just repeat what #Ivo Bosticky said which can be overlooked. Put these lines at the VERY start of the py file.
import matplotlib
matplotlib.use('Agg')
Or one would get error
*/usr/lib/pymodules/python2.7/matplotlib/__init__.py:923: UserWarning: This call to matplotlib.use() has no effect
because the the backend has already been chosen;
matplotlib.use() must be called *before* pylab, matplotlib.pyplot,*
This will resolve all Display issue

I found this snippet to work well when switching between X and no-X environments.
import os
import matplotlib as mpl
if os.environ.get('DISPLAY','') == '':
print('no display found. Using non-interactive Agg backend')
mpl.use('Agg')
import matplotlib.pyplot as plt

When signing into the server to execute the code
use this instead:
ssh -X username#servername
the -X will get rid of the no display name and no $DISPLAY environment variable
error
:)

import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
It works for me.

What system are you on? It looks like you have a system with X11, but the DISPLAY environment variable was not properly set. Try executing the following command and then rerunning your program:
export DISPLAY=localhost:0

One other thing to check is whether your current user is authorised to connect to the X display. In my case, root was not allowed to do that and matplotlib was complaining with the same error.
user#debian:~$ xauth list
debian/unix:10 MIT-MAGIC-COOKIE-1 ae921efd0026c6fc9d62a8963acdcca0
root#debian:~# xauth add debian/unix:10 MIT-MAGIC-COOKIE-1 ae921efd0026c6fc9d62a8963acdcca0
root#debian:~# xterm
source: http://www.debian-administration.org/articles/494 https://debian-administration.org/article/494/Getting_X11_forwarding_through_ssh_working_after_running_su

To make sure your code is portable across Windows, Linux and OSX and for systems with and without displays, I would suggest following snippet:
import matplotlib
import os
# must be before importing matplotlib.pyplot or pylab!
if os.name == 'posix' and "DISPLAY" not in os.environ:
matplotlib.use('Agg')
# now import other things from matplotlib
import matplotlib.pyplot as plt
Credit: https://stackoverflow.com/a/45756291/207661

For Google Cloud Machine Learning Engine:
import matplotlib as mpl
mpl.use('Agg')
from matplotlib.backends.backend_pdf import PdfPages
And then to print to file:
#PDF build and save
def multi_page(filename, figs=None, dpi=200):
pp = PdfPages(filename)
if figs is None:
figs = [mpl.pyplot.figure(n) for n in mpl.pyplot.get_fignums()]
for fig in figs:
fig.savefig(pp, format='pdf', bbox_inches='tight', fig_size=(10, 8))
pp.close()
and to create the PDF:
multi_page(report_name)

import matplotlib
matplotlib.use('Agg')
worked for me as long as I was calling the plotting functions/code directly. But if you are using
from joblib import Parallel, delayed
Parallel and delayed modules for parallelizing your code then you need to add
matplotlib.rcParams.update({'backend': 'Agg'})
line inside your function in order for agg backend to work.

Error with TCL while testing a python code

I'm trying to test a code in python (from internet)
from numpy import corrcoef, sum, log, arange
from numpy.random import rand
from pylab import pcolor, show, colorbar, xticks, yticks
# generating some uncorrelated data
data = rand(10,100) # each row of represents a variable
# creating correlation between the variables
# variable 2 is correlated with all the other variables
data[2,:] = sum(data,0)
# variable 4 is correlated with variable 8
data[4,:] = log(data[8,:])*0.5
# plotting the correlation matrix
R = corrcoef(data)
pcolor(R)
colorbar()
yticks(arange(0.5,10.5),range(0,10))
xticks(arange(0.5,10.5),range(0,10))
show()
but when I execute this script an error message appear
Traceback (most recent call last):
File "test.py", line 20, in <module>
pcolor(R)
File "/usr/lib/pymodules/python2.7/matplotlib/pyplot.py", line 2921, in pcolor
ax = gca()
File "/usr/lib/pymodules/python2.7/matplotlib/pyplot.py", line 803, in gca
ax = gcf().gca(**kwargs)
File "/usr/lib/pymodules/python2.7/matplotlib/pyplot.py", line 450, in gcf
return figure()
File "/usr/lib/pymodules/python2.7/matplotlib/pyplot.py", line 423, in figure
**kwargs)
File "/usr/lib/pymodules/python2.7/matplotlib/backends/backend_tkagg.py", line 79, in new_figure_manager
return new_figure_manager_given_figure(num, figure)
File "/usr/lib/pymodules/python2.7/matplotlib/backends/backend_tkagg.py", line 87, in new_figure_manager_given_figure
window = Tk.Tk()
File "/usr/lib/python2.7/lib-tk/Tkinter.py", line 1767, in __init__
self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: Can't find a usable init.tcl in the following directories:
/usr/local/lib/tcl8.6 /usr/lib/tcl8.6 /lib/tcl8.6 /usr/library /library /tcl8.6.4/library /tcl8.6.4/library
/usr/local/lib/tcl8.6/init.tcl: version conflict for package "Tcl": have 8.6.4, need exactly 8.6.1
version conflict for package "Tcl": have 8.6.4, need exactly 8.6.1
while executing
"package require -exact Tcl 8.6.1"
(file "/usr/local/lib/tcl8.6/init.tcl" line 19)
invoked from within
"source /usr/local/lib/tcl8.6/init.tcl"
("uplevel" body line 1)
invoked from within
"uplevel #0 [list source $tclfile]"
This probably means that Tcl wasn't installed properly.
I tried to reinstall tcl, but I cant install the specific version, can anyone help me please with any idea??

RuntimeError: Invalid DISPLAY variable

I am running my python script in another machine by using ssh command in linux. I have also run this command :
source ~/.bashrc
after logging in the other machine, in order to define the proper paths in the new machine. I was getting the error message for running the following python code lines even I have tried to follow the instruction in this question by defining the backend.
>>> import matplotlib
>>> import pylab as plt
>>> matplotlib.use('Agg')
>>> import numpy as np
>>> x=np.arange(0,2,0.001)
>>> y=np.sin(x)**2+4*np.cos(x)
>>> fig = plt.figure()
>>> plt.plot(x,y,'r.')
The error message
This probably means that Tcl wasn't installed properly.
Traceback (most recent call last):
File "Systematic_Optimised.py", line 513, in <module>
fig = plt.figure()
File "/vol/anaconda/lib/python2.7/site-packages/matplotlib/pyplot.py", line 435, in figure
**kwargs)
File "/vol/anaconda/lib/python2.7/site-packages/matplotlib/backends/backend_qt4agg.py", line 47, in new_figure_manager
return new_figure_manager_given_figure(num, thisFig)
File "/vol/anaconda/lib/python2.7/site-packages/matplotlib/backends/backend_qt4agg.py", line 54, in new_figure_manager_given_figure
canvas = FigureCanvasQTAgg(figure)
File "/vol/anaconda/lib/python2.7/site-packages/matplotlib/backends/backend_qt4agg.py", line 72, in __init__
FigureCanvasQT.__init__(self, figure)
File "/vol/aibn84/data2/zahra/anaconda/lib/python2.7/site-packages/matplotlib/backends/backend_qt4.py", line 68, in __init__
_create_qApp()
File "/vol/anaconda/lib/python2.7/site-packages/matplotlib/backends/backend_qt5.py", line 138, in _create_qApp
raise RuntimeError('Invalid DISPLAY variable')
RuntimeError: Invalid DISPLAY variable
any suggestion how to fix the problem

You must declare matplotlib.use('agg') before import pylab as plt.
Reference

Add
plt.switch_backend('agg')
after
import matplotlib.pyplot as plt

Importing matplotlib on Ubuntu

So I downloaded and installed matplotlib. The weird things is that I can run the examples fine when they were placed in home/user/Desktop but when I moved them to home/user/Documents, they stopped working and I get the below message. Is there something special about the Documents folder that they prevent matplotlib from importing?
Traceback (most recent call last):
File "contour_manual.py", line 4, in <module>
import matplotlib.pyplot as plt
File "/usr/local/lib/python2.7/dist-packages/matplotlib/pyplot.py", line 23, in <module>
from matplotlib.figure import Figure, figaspect
File "/usr/local/lib/python2.7/dist-packages/matplotlib/figure.py", line 18, in <module>
from axes import Axes, SubplotBase, subplot_class_factory
File "/usr/local/lib/python2.7/dist-packages/matplotlib/axes.py", line 8454, in <module>
Subplot = subplot_class_factory()
File "/usr/local/lib/python2.7/dist-packages/matplotlib/axes.py", line 8446, in subplot_class_factory
new_class = new.classobj("%sSubplot" % (axes_class.__name__),
AttributeError: 'module' object has no attribute 'classobj'

Do you have a file new.py in your Documents folder, by any chance? If you have, try renaming it to something else.
The matplotlib module axes.py imports new, and if you have a file new.py lying around in your Documents folder, that will cause Python to load it instead of the built-in new module.

Categories

Resources