I'm new to python and Ipython. I'm following the data analysis with pandas on youtube. the link
I installed Anaconda and then started to use Ipython on Windows 8.1
For several commands, it seems OK
In [2]: print 5
5
But when I tried to followe the tutorial online it seems that my Ipyhon has got some problems,
In [3]: %pylib inline
ERROR: Line magic function `%pylib` not found.
Also, I just copies the code from the tutorials, just very simple codes like this
In [4]:plot(arange(10))
NameError Traceback (most recent call last)
<ipython-input-6-353c92d67d6b> in <module>()
----> 1 plot(arange(10))
NameError: name 'plot' is not defined
After "imported matplotlib", it still didn't work.
Also, the code a = arange(10) didn't work. I have to use it like this:
import numpy as np
a = np.arange(10)
But the tutor in this video didn't use it like this.
I think it should be associated with the configuration with anaconda or Ipython?
But I'm not sure about this and I don't know how to figure it out. I'm using the latest version of anaconda on windows 64bit.
Any suggestions? Thanks!
use %pylab inline or %pylab to enable pylab mode. This will alter the event loop either to show plots inline (notebook) or to display them in different window without interfering the code execution (CLI).
Executing %pylab will set ipython to handle matplotlib nicely, and will also commit from pylab import * that will put numpy and matplotlib commands inside your default namespace.
equivalent way to that, when you invoke IPython, use `ipython --pylab [notebook|qtconsole|etc..]. In windows, you can either do that from console or alter a shortcut to add command line arguments.
You can change IPython system wide configuration to load pylab, see http://ipython.org/ipython-doc/stable/config/overview.html#flags
See this answer for more information: https://stackoverflow.com/a/21457629/3245308
Related
Qt5Agg is necessary to use the mayavi 3D visualization package. I have installed PyQt5 and mayavi using pip in a separate copied conda environment. The default backend then changes from TkAgg to QtAgg. This is a bit weird because in an earlier installation in a different PC the default changed directly to Qt5Agg. I always check the backend using the following commands from the python console :
import matplotlib
matplotlib.get_backend()
Even with the backend being 'QtAgg', I am able to use mayavi from the terminal without any issue but not when I do so in Pycharm. Here I get a non-responsive empty window (image below) :
Image of the non-responsive window
I have been able to get rid of this issue by explicitly using Qt5Agg instead of QtAgg before the plt call :
import matplotlib
matplotlib.use('Qt5Agg')
import matplotlib.pyplot as plt
But I would prefer a better way than using the above in every script that I write. As I had mentioned earlier, I already have mayavi installed and have used it successfully it in Pycharm in a different PC and there the default backend is 'Qt5Agg' and hence there is no need to change the backend explicitly.
Is there anything obvious that I'm overlooking ? Can you please let me know of a way to change the default backend for matplotlib from QtAgg to Qt5Agg after PyQt5 installation using pip ?
Thanks in advance !!
Thanks to #PaulH's comment, I was able to solve the issue. Owing to #mx0's suggestion, I shall now explicitly mention the fix below so that others can also benefit from it.
In a particular conda environment, if matplotlib package is installed, then there will be a 'matplotlibrc' file stored somewhere that defines what the default backend will be whenever matplotlib is imported from that conda environment. The location of this 'matplotlibrc' can be found using the following commands :
import matplotlib
matplotlib.matplotlib_fname()
Please look into the following link if there's any deprecation issue with the above commands :
https://matplotlib.org/stable/tutorials/introductory/customizing.html#customizing-with-matplotlibrc-files
Once the location of the 'matplotlibrc' file is known, open it and simply uncomment one line inside this file. Just change the backend from :
##backend: Agg
to :
backend: Qt5Agg
And that's it. All the plot window troubles in PyCharm will be solved as far as the mayavi 3D visualization package is concerned. For any other use, where a specific backend is necessary, you can also set the default to any other backend of choice.
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.
I'm running some basic code in the Visual Studio Code editor on MacOSX:
import matplotlib.pyplot as plt
import numpy as np
x = np.linspace(0, 20, 100)
plt.plot(x, np.sin(x))
plt.show()
...and can't seem to get the png/svg file image to come up after running this. This also doesn't stop executing and I have to manually terminate the process. However, if I run this directly in the Terminal (each line of code line for line) I get the resulting image. One work-around is to just save the file (plt.savefig('foo.png')). This seems to work - the image is saved in the specified file location. However, it would be good to just see the image come up after running the code.
When running matplotlib codes from the terminal, I experience the same kind of hanging of the application after saving the image to a file. In this case, one 'workaround' that has always worked for me is to turn off blocking. Basically alter your code in this way:
import matplotlib.pyplot as plt
import numpy as np
x = np.linspace(0, 20, 100)
plt.plot(x, np.sin(x))
plt.show(block=False)
input('press <ENTER> to continue')
It's not perfect, but the image is saved correctly and the application stops after you hit ENTER in the terminal. Hope this helps.
I am having a similar issue and I think it is a problem with the exact version of python that vs code is using to run the code.
For reference, I have vscode version 1.52.1 on a mac os Catalina. I installed python via anaconda and created a new environment for python 2.7 (tried with python 3.8 too). I open VSCode by calling code . from the folder I have my simple python codes saved in.
Like OP, I could reproduce the figure if I were to run the code from a python instance called from terminal but not from vscode.
MY SOLUTION:
From vscode, select as python interpreter the one found in /usr/bin/python not the one in ~/opt/anaconda3/env/python27/bin/python
But this is weird, because from a separate terminal window which python returns ~/opt/anaconda3/env/python27/bin/python. This suggests me (though I am no python expert) that there is an issue within vscode about linking the right interpreter with the libraries. Frankly being new to vscode, I find the need to pay attention to these details quite concerning.
I got the same problem, which was driving me nuts. The image was displayed when using Jupyter Notebooks, but not always when using VS Code. I just added one last line_ plt.show() - IMHO unnecessarily - but this worked well.
import matplotlib.pyplot as plt
import matplotlib.image as img
im = img.imread('myimage.png')
plt.imshow(im)
plt.show() # <- added this line and now the image shows every time!
I faced the same issue and here's what I did to solve it.
Since the code runs without any error but also does not generate any plot and needs to be terminated manually, it's difficult to figure out what's going on. I tried running python2.7 test.py
This works, plot is generated but python3 test.py does not work.
So, here's what you need to do -
Run, pip install matplotlib --upgrade to upgrade the matplotlib. This does not resolve the issue but now the error is printed.
"RuntimeError: Python is not installed as a framework" ......
So, finally, to solve the problem, refer to Working with Matplotlib on macOS
Since, I am using Anaconda, all I need to do is conda install python.app and then use pythonw to run all scripts. I hope you also find the solution to your particular case from the FAQ.
Overall, it's a Matplotlib problem, so upgrading (or reinstalling) and trying with different Python versions should get you going.
I'm trying out Jupyter console for the first time, but can't get the %matplotlib inline magic to work. Below is a screenshot of an example session:
The plot shows in a separate window after I run Line 6, and Line 7 doesn't do anything.
When I run %matplotlib --list, inline is given as one of the options:
Available matplotlib backends: ['osx', 'qt4', 'qt5', 'gtk3', 'notebook', 'wx', 'qt',
'nbagg', 'agg', 'gtk', 'tk', 'ipympl', 'inline']
When I try to use another backend, say qt5, it gives an error message because I don't have any Qt installed.
ImportError: Matplotlib qt-based backends require an external PyQt4, PyQt5, or PySide
package to be installed, but it was not found.
Running %matplotlib?? reads:
If you are using the inline matplotlib backend in the IPython Notebook
you can set which figure formats are enabled using the following::
In [1]: from IPython.display import set_matplotlib_formats
In [2]: set_matplotlib_formats('pdf', 'svg')
The default for inline figures sets `bbox_inches` to 'tight'. This can
cause discrepancies between the displayed image and the identical
image created using `savefig`. This behavior can be disabled using the
`%config` magic::
In [3]: %config InlineBackend.print_figure_kwargs = {'bbox_inches':None}
But I don't know if it's something I can tweak around to solve my issue.
When I try it the magic IPython console, it says inline is an Unknown Backend.
UnknownBackend: No event loop integration for u'inline'. Supported event loops are: qt,
qt4, qt5, gtk, gtk2, gtk3, tk, wx, pyglet, glut, osx
I've also found this issue on github after some googling but I don't even know if it's relevant to my situation (most of their conversation didn't make sense to me lol).
Lastly, I'm not sure if this issue is related at all, but here it is, just in case: when I try to open Vim in Jupyter via the !vim command, it glitches pretty badly, preventing me from even exiting out of Jupyter itself without closing the terminal altogther. Vim works perfectly fine when called inside IPython console, however.
I'm using matplotlib 2.0.0.
If anyone could help me figure this out, that'd be great! Thank you!
You’re running a console which is completely text based and incapable of showing images. Therefore, although inline is available, it's not producing inline output.
I'm not sure why it doesn't throw an error, though, which it does in my case:
You can use %matplotlib inline in a GUI console, like Jupyter QTConsole
or in a jupyter notebook in the browser
%matplotlib without the inline works for me (I'm using osx and IPython 7.0.1)
If you're running an old version of ipython try %pylab inline instead. See notes in this tutorial
I'm testing a python program, which contains calling for IPython. But I got errors in the following code:
If I use
%matplotlib inline
I got a syntax error at the "%" symbol.
I found a solution to this problem using:
from IPython import get_ipython
get_ipython().run_line_magic('matplotlib', 'inline')
I got error saying:
AttributeError: 'NoneType' object has no attribute 'run_line_magic'
I'm using Ubuntu 16.04 and running the code via command line. How can I fix this ?
This %matplotlib magic is used to display graphs (of matplotlib.pyplot objects). This needs UI to display. So cannot be display on command prompt.
According to IPython documentation,
If the %matplotlib magic is called without an argument, the output of a plotting command is displayed using the default matplotlib backend in a separate window. Alternatively, the backend can be explicitly requested using, for example:
%matplotlib gtk
A particularly interesting backend, provided by IPython, is the inline backend. This is available only for the Jupyter Notebook and the Jupyter QtConsole. It can be invoked as follows:
%matplotlib inline
Simple solution would be to replace %matplotlib inline with %matplotlib and run it using ipython.
Alternatively, what you could do is download jupyter notebook and run that code there.
Or as #tihom said in comments, you could comment or remove that line and run the code but this wouldn't display the graphs and other things.
You can use pylab mode in ipython. Simply run ipython --pylab in the terminal. That will launch ipython configured to be able to support the matplotlib GUI backend