I have spent over an hour searching, just to figure this simple thing. So, before considering this a duplicate question, please compare my question to any question out there.
This is my code:
import pandas
import matplotlib.pyplot as plt
dataset = pandas.read_csv('international-airline-passengers.csv', usecols=[1], engine='python', skipfooter=1)
print dataset, type(dataset)
plt.plot(dataset)
plt.show()
plt.close()
Firstly, plt.show() to my understanding is a blocking function. So what is the way to close the figure. There is no point in writing plt.close() after it. So where is the right way to put it.
Secondly, how can I make sure all the windows are closed when I execute a new process of the same python code. For example in MATLAB, one could easily say close all in the beginning of their file and it closes all the opened plots which were the result of previous MATLAB code execution. plt.close('all') is not working either.
I am using PyCharm. The results I found for the first situation, might work on IDLE but not in the PyCharm. How can I do it PyCharm.
plt.show(block=False) will do the trick- This is the way you can make this function non-blocking (both in run & debug mode). The main dis-advantage is that if the code ends, the figure is automatically closes...
I had the same problem.
I fix it making the python file in Pycharm to run in only one console. Go to: run---Edit configuration-- check that "single instance only" is activated
There are two ways to run matplotlib, non-interactive and interactive. In non-interactive mode, the default, you are right that plt.show() is blocking. In this case, calling plt.close() is pointless, the code won't stop as long as the figure is open. In interactive mode, however (which can be triggers by plt.ion()), this code will open then immediately close the figure. You would need to put something to wait for user input if you run code like this in a script. Interactive mode, as the name implies, is designed more for running interactively rather than in a script.
As for closing figures from multiple runs of a python script, this isn't possible. If you open multiple instances of MATLAB, close all in one instance won't close the figures in another instance. Running multiple processes of the same python code is the same as opening multiple instances of MATLAB, one run has no knowledge of the others.
Related
I am using VS Code and python. What happens is that in a program like:
import matplotlib.pyplot as plt
import numpy as np
x = np.linspace(1,10)
plt.plot(x, np.sin(x))
plt.show()
plt.plot(x, np.cos(x))
plt.show()
plt.plot(x, np.tan(x))
plt.show()
is that it will stop the exicution of the skript at line 5 and show the plot in a seperate window. It will only continiue to execute the program if I close the plot. Then it will continue until line 7 and stop there.
In other edidors I dont have this behaviour. Like in Spyder. There it will show the polt at the corresponding line, but it will continue the execution of the skript. Is there a way to make the same thing happen in VS Code?
A workaround would be to use plt.figure(). But I am forced to use templates were I can not change the plt.show()'s in the skript. So, I cant use this.
In VSCode, when running and debugging the code, the results will be executed in the same terminal and then output the results, so the above code is executed and output in sequence.
However, according to your description, it is recommended that you use the Jupyter notebook function in VSCode without changing your code. The results will be output in turn and then displayed together.
Use: "Ctrl+Shift+P", "Python: Create Blank New Jupyter Notebook", input the code.
Result:
Reference: Jupyter Notebooks in Visual Studio Code.
If this is not what you want, please describe it in detail and let me know.
Are you looking for this? It turns on "interactive mode". Plotting no longer blocks.
matplotlib.pyplot.ion()
With that, behaviour feels similar to plotting in R, even while in debug mode.
With a single script, I have to produce dozens of figures with matplotlib using spyder. I would like spyder to create figures while I can work with other browsers or windows without interruption. Here were the methods I tried. Let us say that there are 40 plots to be created. Each plot contains multiple subplots
(1) From How do I get interactive plots again in Spyder/IPython/matplotlib?. I used %matplotlib inline. The plots will be created inline at the end of the program. However, the usage of computation memory keeps accumulating. At some point, python will show an error message due to lack of memory and then crash. The message is like: "More than 20 figures have been opened. Figures created through the pyplot interface (matplotlib.pyplot.figure) are retained until explicitly closed and may consume too much memory."
(2) Then, I use plt.close() to close each figure after saving it. The memory issue is resolved. However, even if the figure is not shown, every time python close a figure and open another one, all other browsers and windows will be affected. If I am typing on a window, after the interruption, I have to click the window again in order to continue typing.
Previously, when I used MATLAB, I could simply specify h=figure and then set(h,'visible','off') to avoid this issue. I wonder if I can do similar things with python.
Thank you for the help!
This is highly related to an earlier question by another person a couple of years ago: Matplotlib - Force plot display and then return to main code
I am using Canopy 1.5.5 on MacOSX 10.8.5, with matplotlib 1.4.3.
I will need to load data, look at it, press enter to approve and move to the next dataset (and do that a few thousand times, so it's kind of critical to get this functionality). Here is my MWE:
import numpy as np
from matplotlib import pyplot as plt
plt.ion()
plt.figure()
ind=np.arange(5)
for i in ind:
plt.clf()
plt.scatter(ind,ind+i)
plt.title('this is plot number %i' % i)
plt.show()
u=raw_input("Press any button")
The code seems to do everything EXCEPT actually showing me the plot. If I finish the script (or interrupt it), then I see the current figure.
I have tried everything from the previous answer: with and without interactive mode, with and without plt.show(block=False), every permutation of plt.draw and plt.show, and every backend on my available list.
This seems like a very basic functionality! Please tell me that this can be done. I find it weird that matplolib says here http://matplotlib.org/users/shell.html that "by default the drawing is deferred until the end of the script", but does not have suggestions on how to override the default. Please help!
Your example works for me (my backend is osx), although the figure window appears behind other windows at first. I needed to use alt-tab to raise it to the front.
Try starting your script with the --matplotlib option of IPython. You can select a backend or let it be auto-detected like so: ipython --matplotlib auto yourscript.py
Not sure if you now, but the raw_input function waits for you to press the return key, not just any key.
Edit:
About your last remark: this section explains how to force drawing before the end of the script. This can be done with the draw function. In interactive mode every pyplot command calls draw as well. Drawing in this context means rendering the figure by the backend.
I'm following a book by Wes McKinney and in the section introducing pandas, he's given a simple example of plotting a pandas Data Frame. Here're the lines I wrote:
tz_counts = frame['tz'].value_counts() # frame is a Data Frame
tz_counts[:10] # works fine till here. I can see the key-value I wanted
tz_counts[:10].plot(kind='barh', rot=0)
It just prints a line on screen that says
<matplotlib.axes.AxesSubplot object at 0x3d14ed0>
rather than displaying a plot window as I'd expect with matplotlib's plot function. What's wrong here? How can I make it work?
Matplotlib doesn't show the plot until you tell it to, unless you're in "interactive" mode.
Short Answer: Call plt.show() when you're ready to display the plot.
This starts the gui mainloop of whatever backend you're using, so it is blocking. (i.e. execution will stop until you close the window)
If you want it to show up automatically without stopping execution, you can turn on interactive mode either with plt.ion() or by using ipython --pylab.
However, using --pylab mode in ipython will import all of numpy, matplotlib.pyplot, and a few other things into the global namespace. This is convenient for interactive use, but teaches very bad habits and overwrites functions in the standard library (e.g. min, max, etc).
You can still use matplotlib's interactive mode in ipython without using "pylab" mode to avoid the global import. Just call plt.ion()
Matplotlib's default TkAgg backend will work in interactive mode with any python shell (not just ipython). However, other backends can't avoid blocking further execution without the gui mainloop being run in a separate thread. If you're using a different backend, then you'll need to tell ipython this with the --gui=<backend> option.
Try using:
%matplotlib
tz_counts = frame['tz'].value_counts()
tz_counts[:10].plot(kind='barh', rot=0)
Using % matplotlib prevents importing * from pylab and numpy which in turn prevents variable clobbering.
I am working in linux and I don't know why using python and matplotlib commands draws me only once the chart I want.
The first time I call show() the plot is drawn, wihtout any problem, but not the second time and the following.
I close the window showing the chart between the two calls. Do you know why and hot to fix it?
Thanks AFG
from numpy import *
from pylab import *
data = array( [ 1,2,3,4,5] )
plot(data)
[<matplotlib.lines.Line2D object at 0x90c98ac>]
show() # this call shows me a plot
#..now I close the window...
data = array( [ 1,2,3,4,5,6] )
plot(data)
[<matplotlib.lines.Line2D object at 0x92dafec>]
show() # this one doesn't shows me anything
in windows this works perfect:
from pylab import *
plot([1,2,3,4])
[<matplotlib.lines.Line2D object at 0x03442C10>]
#close window here
plot([1,2,3,4])
[<matplotlib.lines.Line2D object at 0x035BC570>]
did you try with:
from matplotlib import interactive
interactive(True)
sometimes matplotlib produces some headaches because we have to remember that some options are set in matplotlibrc (such as the backend or the interactive parameters). If you use matplotlib from different editors (IDLE-tk, pycrust-wxpython) or alternating interactive with scripting, then you have to take into account that the configuration that works in one mode could give you problems in the other mode and must be modified programmatically or using a dedicated configuration file.
The example I give, works directly (and without show()) because in matplotlibrc I have interactive set to True as default
You likely have conflicts between your editor/IDE windowing system, and your plot windows.
A very good way around this is to use IPython. IPython is a great interactive environment, and has worked out these issues plus has many other advantages. At the beginning, start IPython with the command (from a terminal window) ipython -pylab to put it in the interactive pylab mode.
I'm guessing that you are doing this in IDLE on Windows because that's where I've noticed this same problem.
From what I've deduced, there is a problem with using the TkAgg backend,which comes with the basic Python dist and appears to be the default for matplotlib, when using matplotlib with IDLE. It has something to do with the way IDLE uses subprocesses because if I start IDLE with the -n option, which disables subprocesses, I don't have this problem. An easy way to start it IDLE with the -n option on Windows is to right click and file and select 'Open with IDLE'. If you do this you should get an IDLE shell which says
=== No Subprocess ===
just above the prompt. For instance, borrowing code from joaquin's solution, you could try this simple code:
from matplotlib import interactive
interactive(True)
from pylab import *
plot([1,2,3,4])
then close the window and type the last line into the console again. It works for me in IDLE with the -n option.
So what can you do? You can always run IDLE in the mode without subprocesses, but there are dangers to that. You can use a different IDE. Many people suggest IPython though I'm not sold on it yet myself. You could also try a different backend for matplotlib. I'm going to try that in a little while cause I've been wondering whether it will work.
show() is only meant to be used once in a program, at the very end: it is a never ending loop that checks for events in the graphic windows.
The normal way of doing what you want is:
# … plot …
draw() # Draws for real
raw_input() # Or anything that waits for user input
# … 2nd plot …
draw()
raw_input()
# Last plot
show() # or, again, draw(); raw_input()
You could try to see whether this works for you.
Alternatively, you can try to change the backend, as some backends work better than others:
import matplotlib
matplotlib.use('TkAgg') # For other backends, do matplotlib.use('') in a shell