My plot in ipython does not show with pyplot.show()

Question

Help required displaying matplotlib plots in ipython. I did not forget to call pyplot.show().

$ ipython --pylab

import matplotlib.pyplot as plt
plt.plot(range(20), range(20))

It returns matplotlib.lines.Line2D at 0xade2b2c as the output.

plt.show()

Nothing happens. No error message. No new window. I installed matplotlib with pip, and no error messages occurred.

Details:

I use,

• Ubuntu
• IPython v0.11
• Python v2.6.6
• matplotlib v1.0.1

Slav

pylab is dead. Which is the recommended way to plot: matplotlib or pylab?. Disregard answers with pylab. – Davedaveda

Answer 1

If I set my backend to template in ~/.matplotlib/matplotlibrc, then I can reproduce your symptoms:

~/.matplotlib/matplotlibrc:

# backend      : GtkAgg
backend      : template

Note that the file matplotlibrc may not be in directory ~/.matplotlib/. In this case, the following code shows where it is:

>>> import matplotlib
>>> matplotlib.matplotlib_fname()

---

In [1]: import matplotlib.pyplot as p

In [2]: p.plot(range(20),range(20))
Out[2]: [<matplotlib.lines.Line2D object at 0xa64932c>]

In [3]: p.show()

---

If you edit ~/.matplotlib/matplotlibrc and change the backend to something like GtkAgg, you should see a plot. You can list all the backends available on your machine with

import matplotlib.rcsetup as rcsetup
print(rcsetup.all_backends)

It should return a list like:

['GTK', 'GTKAgg', 'GTKCairo', 'FltkAgg', 'MacOSX', 'QtAgg', 'Qt4Agg',
'TkAgg', 'WX', 'WXAgg', 'CocoaAgg', 'agg', 'cairo', 'emf', 'gdk', 'pdf',
'ps', 'svg', 'template']

Reference:

• Customizing matplotlib

Mesencephalon

Answer 2

I ran into the exact same problem on Ubuntu 12.04, because I installed matplotlib (within a virtualenv) using

pip install matplotlib

To make long story short, my advice is: don't try to install matplotlib using pip or by hand; let a real package manager (e.g. apt-get / synaptic) install it and all its dependencies for you.

Unfortunately, matplotlib's backends (alternative methods for actually rendering your plots) have all sorts of dependencies that pip will not deal with. Even worse, it fails silently; that is, pip install matplotlib appears to install matplotlib successfully. But when you try to use it (e.g. pyplot.show()), no plot window will appear. I tried all the different backends that people on the web suggest (Qt4Agg, GTK, etc.), and they all failed (i.e. when I tried to import matplotlib.pyplot, I get ImportError because it's trying to import some dependency that's missing). I then researched how to install those dependencies, but it just made me want to give up using pip (within virtualenv) as a viable installation solution for any package that has non-Python package dependencies.

The whole experience sent me crawling back to apt-get / synaptic (i.e. the Ubuntu package manager) to install software like matplotlib. That worked perfectly. Of course, that means you can only install into your system directories, no virtualenv goodness, and you are stuck with the versions that Ubuntu distributes, which may be way behind the current version...

Amimia

Answer 3

Add %matplotlib inline once to the notebook, prior to plotting.

Cassowary

This question is about ipython, not jupyter notebooks – Rotl

Answer 4

Just type:

plt.ion()

See https://www.youtube.com/watch?v=1zmV8lZsHF4 at 23:30 !

plt is used because of my import: import matplotlib.pyplot as plt

I'm using python2.7 on a mac with iTerm2.

Lohr

Answer 5

For future reference,

I have encountered the same problem -- pylab was not showing under ipython. The problem was fixed by changing ipython's config file {ipython_config.py}. In the config file

c.InteractiveShellApp.pylab = 'auto'

I changed 'auto' to 'qt' and now I see graphs

Hoodoo

Answer 6

What solved my problem was just using the below two lines in ipython notebook at the top

%matplotib inline
%pylab inline

And it worked. I'm using Ubuntu16.04 and ipython-5.1

Gasconade

pylab is dead. Which is the recommended way to plot: matplotlib or pylab? – Davedaveda

Answer 7

Adding the following two lines before importing pylab seems to work for me

import matplotlib
matplotlib.use("gtk")

import sys
import pylab
import numpy as np

Butyrin

Answer 8

I had to install matplotlib from source to get this to work. The key instructions (from http://www.pyimagesearch.com/2015/08/24/resolved-matplotlib-figures-not-showing-up-or-displaying/) are:

$ workon plotting
$ pip uninstall matplotlib
$ git clone https://github.com/matplotlib/matplotlib.git
$ cd matplotlib
$ python setup.py install

By changing the backend, as @unutbu says, I just ran into loads more problems with all the different backends not working either.

Commorant

Answer 9

Similar to @Rikki, I solved this problem by upgrading matplotlib with pip install matplotlib --upgrade. If you can't upgrade uninstalling and reinstalling may work.

pip uninstall matplotlib
pip install matplotlib

Geer

Answer 10

After running your code include:

import pylab as p
p.show()

Variorum

pylab is dead. Which is the recommended way to plot: matplotlib or pylab? – Davedaveda

Answer 11

If you are working with yolov5 the fixes described here might not work as in my case. YOLOv5 developers have turned off the preview of the images using plt.show(), so most likely this will happen to you. To resolve make sure that your environment is correctly configured using requirements.txt file that comes with yolov5 and then use the workaround:

import torch
import matplotlib

model = torch.hub.load('ultralytics/yolov5', 'yolov5s') # Load model first
matplotlib.use('TkAgg') # Change backend after loading model

as described here: https://github.com/ultralytics/yolov5/issues/2779 you can also try another backend from the ones mentioned above like 'Qt4Agg' or smth else.

Foothill

This comment was absolutely brilliant - and saved the day. I had changed the backend at the start of the program (as I'd been doing some plot tests as it wasn't showing up), but never thought that Yolov5 - which I use - was re-setting it later on. This literally solved about 3-4 hours of hair-pulling (if only I had seen this earlier, I would have some hair left!) – Awful

Answer 12

Be sure to have this startup script enabled : ( Preferences > Console > Advanced Options )

/usr/lib/python2.7/dist-packages/spyderlib/scientific_startup.py

If the standard PYTHONSTARTUP is enabled you won't have an interactive plot

Crosspatch

Answer 13

For me the problem happens if I simply create an empty matplotlibrc file under ~/.matplotlib on macOS. Adding "backend: macosx" in it fixes the problem.

I think it is a bug: if backend is not specified in my matplotlibrc it should take the default value.

Rollicking

Answer 14

if you are a nube from ruby, don't forget the parenthesis - show()

Nichollenicholls

Answer 15

This is not a great long-term solution, but if none of this is working for you, you can get around it by using this instead of p.show():

p.savefig("output_plot.png")

This will create the plot image in the same directory. You can open it separately in a normal image viewer.

Minx

Answer 16

I found that I needed window = Tk() and then window.mainloop()

Guideboard

Answer 17

For Ubuntu 12.04:

sudo apt-get install python-qt4
virtualenv .env --no-site-packages
source .env/bin/activate
easy_install -U distribute
ln -s /usr/lib/python2.7/dist-packages/PyQt4 .
ln -s /usr/lib/python2.7/dist-packages/sip.so .
pip install matplotlib

Blunger