Plotting window doesn't show up with pylab [duplicate] - python

I just installed matplotlib in Ubuntu 9.10 using the synaptic package system.
However, when I try the following simple example
>>> from pylab import plot;
>>> plot([1,2,3],[1,2,3])
[<matplotlib.lines.Line2D object at 0x9aa78ec>]
I get no plot window. Any ideas on how to get the plot window to show?


You can type
import pylab
pylab.show()
or better, use ipython -pylab.
Since the use of pylab is not recommended anymore, the solution would nowadays be
import matplotlib.pyplot as plt
plt.plot([1,2,3])
plt.show()


pylab.show() works but blocks (you need to close the window).
A much more convenient solution is to do pylab.ion() (interactive mode on) when you start: all (the pylab equivalents of) pyplot.* commands display their plot immediately. More information on the interactive mode can be found on the official web site.
I also second using the even more convenient ipython -pylab (--pylab, in newer versions), which allows you to skip the from … import … part (%pylab works, too, in newer IPython versions).


Try this:
import matplotlib
matplotlib.use('TkAgg')
BEFORE import pylab


The code snippet below works on both Eclipse and the Python shell:
import numpy as np
import matplotlib.pyplot as plt
# Come up with x and y
x = np.arange(0, 5, 0.1)
y = np.sin(x)
# Just print x and y for fun
print x
print y
# Plot the x and y and you are supposed to see a sine curve
plt.plot(x, y)
# Without the line below, the figure won't show
plt.show()


Any errors show up? This might an issue of not having set the backend. You can set it from the Python interpreter or from a config file (.matplotlib/matplotlibrc) in you home directory.
To set the backend in code you can do
import matplotlib
matplotlib.use('Agg')
where 'Agg' is the name of the backend. Which backends are present depend on your installation and OS.
http://matplotlib.sourceforge.net/faq/installing_faq.html#backends
http://matplotlib.org/users/customizing.html


Modern IPython uses the "--matplotlib" argument with an optional backend parameter. It defaults to "auto", which is usually good enough on Mac and Windows. I haven't tested it on Ubuntu or any other Linux distribution, but I would expect it to work.
ipython --matplotlib


If you encounter an issue in which pylab.show() freezes the IPython window (this may be Mac OS X specific; not sure), you can cmd-c in the IPython window, switch to the plot window, and it will break out.
Apparently, future calls to pylab.show() will not freeze the IPython window, only the first call. Unfortunately, I've found that the behavior of the plot window / interactions with show() changes every time I reinstall matplotlib, so this solution may not always hold.


If you are starting IPython with the --pylab option, you shouldn't need to call show() or draw(). Try this:
ipython --pylab=inline


--pylab no longer works for Jupyter, but fortunately we can add a tweak in the ipython_config.py file to get both pylab as well as autoreload functionalities.
c.InteractiveShellApp.extensions = ['autoreload', 'pylab']
c.InteractiveShellApp.exec_lines = ['%autoreload 2', '%pylab']


If you are user of Anaconda and Spyder then best solution for you is that :
Tools
-->
Preferences
-->
Ipython console
-->
Graphic Section
Then in the Support for graphics (Matplotlib) section:
select two avaliable options
and in the Graphics Backend:
select Automatic


Another possibility when using easy_install is that you need to require the most recent version of matplotlib.
Try:
import pkg_resources
pkg_resources.require("matplotlib")
before you import matplotlib or any of its modules.

Related

How can I display an image on VS Code and PyCharm?

I want to choose the best IDE for Python programming so I'm testing different softwares but I have problem.
When I try this code blocks on VS Code I don't see any error but the image is not showing
import matplotlib.pyplot as plt
import matplotlib.image as mpimg
image = mpimg.imread('exit-ramp.jpg')
plt.imshow(image)
VS Code
When I try run the same code on PyCharm I see some errors
PyCharm
But when I run the same code on Jupyter Notebook it works. What can I do?

Bro, try that:
import matplotlib.pyplot as plt
import matplotlib.image as mpimg
image = mpimg.imread('exit-ramp.jpg')
plt.imshow(image)
plt.show()
i've made a test in my vscode.
Few weeks ago i used a lot pycharm... but i get some library errors with pandas and pycharm its a little bit heavy.
VSCODE its light and i didnt get any library error that i had with pycharm.

I believe this is a backend problem to be changed in matplotlib. If you start your Python shell whether you are in a bash shell or in vscode, you should use a backend that will show the plot. Otherwise the plt.show() call is required.
So, one solution is to change the backend either manually in you Python shell or when starting the Python shell as explained here below.
Note, however, that I always use the qt5 backend but got the same issue as yours: no plot appears. I changed to the Qt5Agg backend and it worked for me (providing PyQt5 is installed).
So, first solution, you can try to set the backend when starting the Python shell:
ipython --pylab Qt5Agg
You should use a GUI backend amongst the possible backend. If you do not known, try to replace Qt5Agg by auto
The second solution consists in changing the backend manually once in the Python shell:
import matplotlib as plt
plt.use('Qt5Agg')

Right click on your code -> Run current file in interactive window.

Jupyter Notebook ImportError, %matplotlib qt

I am using
%matplotlib inline
to display plots inside the notebook. I would like to disable this for several cells. So, I try
%matplotlib qt
This outputs the following error:
ImportError: Matplotlib qt-based backends require an external PyQt4, PyQt5,
or PySide package to be installed, but it was not found.
I am not sure how to solve this, as everything is up to date.
How can I solve the above?
Is there another way to disable %matplotlib inline in a certain cell without restarting the entire kernel?

You might be able to use plt.switch_backend, although as the documentation states, this is an experimental feature. The following works for me, using matplotlib 1.5 and an IPython 4.0.1:
In [1]: from matplotlib import pyplot as plt
In [2]: import numpy as np
# plot appears inline (default)
In [3]:plt.plot(np.random.randn(10))
Out[3]:[<matplotlib.lines.Line2D at 0x7fac4408e390>]
In [4]: plt.switch_backend('QtAgg4')
# plot appears inside a separate Qt4 window
In [5]:plt.plot(np.random.randn(10))
Out[5]:[<matplotlib.lines.Line2D at 0x7fac3b408a90>]
You might need to change 'QtAgg4' according to whichever version of PyQt you have installed - this could be the cause of the error you mentioned in the question. Another interactive backend that should work on Mac would be 'CocoaAgg'. If the images are very large you could also use the 'Agg' backend to suppress plotting altogether, and instead save the resulting figure(s) straight to disk.

If you don't have a specific backend installed use "agg":
import matplotlib
matplotlib.use('agg')
import matplotlib.pyplot as plt
Reference: https://github.com/matplotlib/matplotlib/issues/9017

Pycharm does not show plot

Pycharm does not show plot from the following code:
import pandas as pd
import numpy as np
import matplotlib as plt
ts = pd.Series(np.random.randn(1000), index=pd.date_range('1/1/2000', periods=1000))
ts = ts.cumsum()
ts.plot()
What happens is that a window appears for less than a second, and then disappears again.
Using the Pyzo IEP IDE (using same interpreter) on the same code the plot shows as expected.
...So the problem must be with some setting on Pycharm.
I've tried using both python.exe and pythonw.exe as interpreter both with same results.
This is my sys_info:
C:\pyzo2014a\pythonw.exe -u C:\Program Files (x86)\JetBrains\PyCharm Community Edition 3.4.1\helpers\pydev\pydevconsole.py 57315 57316
PyDev console: using IPython 2.1.0import sys; print('Python %s on %s' % (sys.version, sys.platform))
Python 3.4.1 |Continuum Analytics, Inc.| (default, May 19 2014, 13:02:30) [MSC v.1600 64 bit (AMD64)] on win32
sys.path.extend(['C:\\Users\\Rasmus\\PycharmProjects\\untitled2'])
In[3]: import IPython
print(IPython.sys_info())
{'commit_hash': '681fd77',
'commit_source': 'installation',
'default_encoding': 'UTF-8',
'ipython_path': 'C:\\pyzo2014a\\lib\\site-packages\\IPython',
'ipython_version': '2.1.0',
'os_name': 'nt',
'platform': 'Windows-8-6.2.9200',
'sys_executable': 'C:\\pyzo2014a\\pythonw.exe',
'sys_platform': 'win32',
'sys_version': '3.4.1 |Continuum Analytics, Inc.| (default, May 19 2014, '
'13:02:30) [MSC v.1600 64 bit (AMD64)]'}

Just use
import matplotlib.pyplot as plt
plt.show()
This command tells the system to draw the plot in Pycharm.
Example:
plt.imshow(img.reshape((28, 28)))
plt.show()

I realize this is old but I figured I'd clear up a misconception for other travelers. Setting plt.pyplot.isinteractive() to False means that the plot will on be drawn on specific commands to draw (i.e. plt.pyplot.show()). Setting plt.pyplot.isinteractive() to True means that every pyplot (plt) command will trigger a draw command (i.e. plt.pyplot.show()). So what you were more than likely looking for is plt.pyplot.show() at the end of your program to display the graph.
As a side note you can shorten these statements a bit by using the following import command import matplotlib.pyplot as plt rather than matplotlib as plt.

I tried different solutions but what finally worked for me was plt.show(block=True). You need to add this command after the myDataFrame.plot() command for this to take effect. If you have multiple plot just add the command at the end of your code. It will allow you to see every data you are plotting.

I had the same problem. Check wether plt.isinteractive() is True. Setting it to 'False' helped for me.
plt.interactive(False)

import matplotlib
matplotlib.use('TkAgg')
Works for me. (PyCharm/OSX)

I test in my version of Pycharm (Community Edition 2017.2.2), you may need to announce both plt.interactive(False) and plt.show(block=True) as following:
import numpy as np
import matplotlib.pyplot as plt
x = np.linspace(0, 6.28, 100)
plt.plot(x, x**0.5, label='square root')
plt.plot(x, np.sin(x), label='sinc')
plt.xlabel('x label')
plt.ylabel('y label')
plt.title("test plot")
plt.legend()
plt.show(block=True)
plt.interactive(False)

I have found a solution. This worked for me:
import numpy as np
import matplotlib.pyplot as plt
points = np.arange(-5, 5, 0.01)
dx, dy = np.meshgrid(points, points)
z = (np.sin(dx)+np.sin(dy))
plt.imshow(z)
plt.colorbar()
plt.title('plot for sin(x)+sin(y)')
plt.show()

Soon after calling
plt.imshow()
call
plt.show(block = True)
You will get the matplotlib popup with the image.
This is a blocking way. Further script will not run until the pop is closed.

None of the above worked for me but the following did:
Disable the checkbox (Show plots in tool window) in pycharm settings > Tools > Python Scientific.
I received the error No PyQt5 module found. Went ahead with the installation of PyQt5 using :
sudo apt-get install python3-pyqt5
Beware that for some only first step is enough and works.

With me the problem was the fact that matplotlib was using the wrong backend. I am using Debian Jessie.
In a console I did the following:
import matplotlib
matplotlib.get_backend()
The result was: 'agg', while this should be 'TkAgg'.
The solution was simple:
Uninstall matplotlib via pip
Install the appropriate libraries: sudo apt-get install tcl-dev tk-dev python-tk python3-tk
Install matplotlib via pip again.

Just add plt.pyplot.show(), that would be fine.
The best solution is disabling SciView.

I tested in my version on PyCharm 2017.1.2. I used interactive (True) and show (block=True).
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
ts = pd.Series(np.random.randn(1000), index=pd.date_range('1//2000',periods=1000))
ts = ts.cumsum()
plt.interactive(True)
ts.plot()
plt.show(block=True)

My env: macOS & anaconda3
This works for me:
matplotlib.use('macosx')
or interactive mode:
matplotlib.use('TkAgg')

i had this problem and i could solve it , you can test my way..
disable "show plots in tool window" from setting-->tools-->python scientific

Comment from DanT fixed this for me, matplotlib with pycharm on linux with the GTKagg backend. Upon importing matplotlib I would get the following error:
>>> import matplotlib as mpl
Backend GTKAgg is interactive backend. Turning interactive mode on.
Failed to enable GUI event loop integration for 'gtk'
When plotting something like so:
from matplotlib import pyplot as plt
plt.figure()
plt.plot(1,2)
plt.show()
A figure screen would pop up but no charts appear.
using:
plt.show(block=True)
displays the graphic correctly.

For beginners, you might also want to make sure you are running your script in the console, and not as regular Python code. It is fairly easy to highlight a piece of code and run it.

In my case, I wanted to do the following:
plt.bar(range(len(predictors)), scores)
plt.xticks(range(len(predictors)), predictors, rotation='vertical')
plt.show()
Following a mix of the solutions here, my solution was to add before that the following commands:
matplotlib.get_backend()
plt.interactive(False)
plt.figure()
with the following two imports
import matplotlib
import matplotlib.pyplot as plt
It seems that all the commands are necessary in my case, with a MBP with ElCapitan and PyCharm 2016.2.3. Greetings!

In non-interactive env, we have to use plt.show(block=True)

For those who are running a script inside an IDE (and not working in an interactive environment such as a python console or a notebook), I found this to be the most intuitive and the simplest solution:
plt.imshow(img)
plt.waitforbuttonpress()
It shows the figure and waits until the user clicks on the new window. Only then it resume the script and run the rest of the code.

I was able to get a combination of some of the other suggestions here working for me, but only while toggling the plt.interactive(False) to True and back again.
plt.interactive(True)
plt.pyplot.show()
This will flash up the my plots. Then setting to False allowed for viewing.
plt.interactive(False)
plt.pyplot.show()
As noted also my program would not exit until all the windows were closed. Here are some details on my current run environment:
Python version 2.7.6
Anaconda 1.9.2 (x86_64)
(default, Jan 10 2014, 11:23:15)
[GCC 4.0.1 (Apple Inc. build 5493)]
Pandas version: 0.13.1

One property need to set for pycharm.
import matplotlib.pyplot as plt
plt.interactive(False) #need to set to False
dataset.plot(kind='box', subplots=True, layout=(2,2), sharex=False, sharey=False)
plt.show()

Change import to:
import matplotlib.pyplot as plt
or use this line:
plt.pyplot.show()

I'm using Ubuntu and I tried as #Arie said above but with this line only in terminal:
sudo apt-get install tcl-dev tk-dev python-tk python3-tk
And it worked!

In Pycharm , at times the Matplotlib.plot won't show up.
So after calling plt.show() check in the right side toolbar for SciView. Inside SciView every generated plots will be stored.

I was facing above error when i am trying to plot histogram and below points worked for me.
OS : Mac Catalina 10.15.5
Pycharm Version : Community version 2019.2.3
Python version : 3.7
I changed import statement as below (from - to)
from :
import matplotlib.pylab as plt
to:
import matplotlib.pyplot as plt
and plot statement to below (changed my command form pyplot to plt)
from:
plt.pyplot.hist(df["horsepower"])
# set x/y labels and plot title
plt.pyplot.xlabel("horsepower")
plt.pyplot.ylabel("count")
plt.pyplot.title("horsepower bins")
to :
plt.hist(df["horsepower"])
# set x/y labels and plot title
plt.xlabel("horsepower")
plt.ylabel("count")
plt.title("horsepower bins")
use plt.show to display histogram
plt.show()

imshow() function not working

I'm working on a program in python with packages numpy,scipy and matplotlib.pyplot. This is my code:
import matplotlib.pyplot as plt
from scipy import misc
im=misc.imread("photosAfterAverage/exampleAfterAverage1.jpg")
plt.imshow(im, cmap=plt.cm.gray)
for some reason the image isn't showing up (checked if I got the image, in that part it's all fine- I can print the array.).

You need to call plt.show() to display the image. Or use ipython --pylab for an interactive shell that is matplotlib aware.

"Interactive mode may also be turned on via matplotlib.pyplot.ion(), and turned off via matplotlib.pyplot.ioff()" cf. matplotlib user guide.

Python matplotlib

I'm having trouble getting the window for matplotlib to show.
I've downloaded python 3.3, matplotlib for python 3.3, and numpy.
I've also installed python tools for Visual Studio 2012 so I can create python solutions in that environment.
With all that out of the way... I'm running this EXTREMELY simple script:
import numpy as np
import matplotlib.pyplot as plt
import pylab
# Come up with x and y
x = np.arange(0, 5, 0.1)
y = np.sin(x)
# plot the x and y and you are supposed to see a sine curve
plt.plot(x, y)
# without the line below, the figure won't show
pylab.show()
This compiles with no warnings or errors, but only my console window displays; no graph or interactive window ever shows up. I tried running the scrip from the command prompt thinking maybe the visual studio environment was throwing it off, but it still didn't work.
I also tried running with python 2.7 and it also didn't work.
Every tutorial I found confirmed that this should be working. I'm pulling my hair out and would praise any help at this point.

You should type
plt.show()
instead.

You need to put
plt.figure()
to make the figure window before you start plotting information to it
If you are using a GUI console such as Spyder, make sure you have turned on interactive plots so that it plots to a separate window and not inline into the console

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