Matplotlib shows nothing in Jupyter notebook - python

I am working with Matplotlib and came across with Object Oriented Method to create plots with Matplotlib. So I wrote the following code in Jupyter Notebook
import matplotlib.pyplot as plt
import numpy as np
%matplotlib inline
x=np.linspace(0,5,11)
y=x**2
fig=plt.figure()
axes=fig.add_axes([0.1,0.1,0.8,0.8])
axes.plot(x,y)
But I don't get any plot after running it. I tried looking other answers but couldn't solve my problem. So, my question is how do Object Oriented Interface in Matplotlib actually works and how and why it is better than functional method of Matplotlib?
Thanks.

Related

Jupyter and %matplotlib inline lost axis

I am having a really weird issue with using the %matplotlib inline code in my jupyter notebook for plotting graphs using both pyplot and the pandas plotting function.
The problem is they show up without any axes, and basically just show the graph area without anything aside from data points.
I found adding:
import matplotlib as mpl
mpl.rcParams.update(mpl.rcParamsDefault)
reverse it, but I find it odd that should do that every time as the effect disappears as soon as I run %matplotlib inlinecommand.
an example could be
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
%matplotlib inline
plt.scatter(A,A)
plt.tight_layout()
plt.xlabel('here')
plt.show()
This would generate the graph below:
Weird enough if I uses the savefig it get plotted with the axis, if I uses the right-click -> new output -> save as figure, I also get the graph with the figures !!
like this:
Can anyone help me understand what is wrong, which global setting did I mess up, and how do I revert it?
(I don't remember messing around with any settings aside from some settings for pandas, but don't think they should have had an impact)
as mentioned running mpl.rcParams.update(mpl.rcParamsDefault) command does bring it back to normal until I run %matplotlib inline` again !!
Any help would be much appreciated.
Okay I am sorry I think I can answer the question myself now.
With the helpfull #Mr. T asking for the imgur link made me realize what was going on. I had starting using the dark jupyter lab theme, and the graph would generate plots with transparent background, ie. the text and lines where there, but I just couldn't see them.
The trick is to change the background color preferably globally, but that will be a task for tomorrow.

Problem with import matplotlib.pyplot as plt in python (Anaconda - Spyder) [duplicate]

This question already has answers here:
How to display a graph in ipython notebook
(2 answers)
Closed 2 years ago.
i'm newbie in python but i don't know how to solve this problem
I need an histogram in my code. I use this:
import matplotlib.pyplot as plt
plt.hist(datos["Ozone"], bins=10)
Note: datos is a dataframe.
I tested with other more basic examples, but never show the graph of the histogram.
I think is a problem with the Console, but i don't know how solve the problem.
You have to write:
plt.show()
at the end to see your plot.
EDIT:
In case you are using jupyter notebooks, there is no need for plt.show(). You can just add two lines of code as follows:
import matplotlib.pyplot as plt
%matplotlib qt
%matplotlib inline
plt.hist(datos["Ozone"], bins=10)

Poliastro plot not showing up in Jupyter

Just started learning poliastro and it's already not working.
Tried plotting their example code here https://github.com/poliastro/poliastro:
%matplotlib inline
from poliastro.examples import molniya
molniya.plot()
but nothing came out :( Doesn't work with plt.show() either

Why am I getting UserWarning: Matplotlib is currently using ps, which is a non-GUI backend, so cannot show the figure

This is not in a jupyter notebook so this is not a duplicate of this question, but my code is:
from gluoncv import model_zoo, data, utils
from matplotlib import pyplot as plt
...
plt.show()
The error I'm getting is:
/figure.py:445: UserWarning: Matplotlib is currently using ps, which is a non-GUI backend, so cannot show the figure.
% get_backend())
I created a repl at https://repl.it/#shamoons/WelloffHarmfulMineral
If it matters, I'm using OS X. What do I need to do to get the image to show?
You can use
matplotlib.use("TkAgg")
instead of
matplotlib.use("PS")
when developing on MacOS.
Please note that the import should be before importing plt, like this:
import matplotlib
matplotlib.use('TkAgg')
from matplotlib import pyplot as plt
matplotlib.use('PS') and plt.show() are mutually exclusive. You need to decide:
Do you want to show the figure on screen? Solution: Remove the line matplotlib.use('PS').
Do you want to use the PS backend? This seems unlikely, because there is rarely a reason to set the backend to something non-interactive unless working on a server. Anyways, solution: Replace plt.show() by plt.savefig("filname.ps").

Displaying image with matplotlib in ipython

How can I display an image imported with numpy package using matplotlib in ipython?
It should be fairly easy with the command
import numpy as np
import matplotlib.pyplot as plt
im = np.array(Image.open('image.jpg'))
plt.imshow(im)
But the image does not show and I just get the output
<matplotlib.image.AxesImage at 0x7fb38e10ff10>
You must call plt.show() to actually bring up the windows.
You can get around this by using interactive mode. But for scripts it is better to simply call show() after completing all your plotting commands.
In IPython or Jupyter notebooks, if you want to show images as inline in the notebook and not in a separate window, implement the code shown below.
import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline
im = np.array(Image.open('image.jpg'))
plt.imshow(im)
plt.show()

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