How do I tell matplotlib that I am done with a plot?

Question

The following code plots to two PostScript (.ps) files, but the second one contains both lines.

import matplotlib
import matplotlib.pyplot as plt
import matplotlib.mlab as mlab

plt.subplot(111)
x = [1,10]
y = [30, 1000]
plt.loglog(x, y, basex=10, basey=10, ls="-")
plt.savefig("first.ps")


plt.subplot(111)
x = [10,100]
y = [10, 10000]
plt.loglog(x, y, basex=10, basey=10, ls="-")
plt.savefig("second.ps")

How can I tell matplotlib to start afresh for the second plot?

Asked By: Stefano Borini

||

Source

Answer 1

You can use figure to create a new plot, for example, or use close after the first plot.

Answered By: David Cournapeau

Answer 2

There is a clear figure command, and it should do it for you:

plt.clf()

If you have multiple subplots in the same figure

plt.cla()

clears the current axes.

Answered By: randlet

Answer 3

As stated from @DavidCournapeau, use figure().

import matplotlib
import matplotlib.pyplot as plt
import matplotlib.mlab as mlab

plt.figure()
x = [1,10]
y = [30, 1000]
plt.loglog(x, y, basex=10, basey=10, ls="-")
plt.savefig("first.ps")


plt.figure()
x = [10,100]
y = [10, 10000]
plt.loglog(x, y, basex=10, basey=10, ls="-")
plt.savefig("second.ps")

Or subplot(121) / subplot(122) for the same plot, different position.

import matplotlib
import matplotlib.pyplot as plt
import matplotlib.mlab as mlab

plt.subplot(121)
x = [1,10]
y = [30, 1000]
plt.loglog(x, y, basex=10, basey=10, ls="-")

plt.subplot(122)
x = [10,100]
y = [10, 10000]
plt.loglog(x, y, basex=10, basey=10, ls="-")
plt.savefig("second.ps")

Answered By: lmount

Answer 4

Just enter plt.hold(False) before the first plt.plot, and you can stick to your original code.

Answered By: Dirklinux

Answer 5

If you’re using Matplotlib interactively, for example in a web application, (e.g. ipython) you maybe looking for

plt.show()

instead of plt.close() or plt.clf().

Answered By: Damo

Answer 6

If none of them are working then check this.. say if you have x and y arrays of data along respective axis. Then check in which cell(jupyter) you have initialized x and y to empty. This is because , maybe you are appending data to x and y without re-initializing them. So plot has old data too. So check that..

Answered By: Seeni

Answer 7

From the source code of matplotlib.pyplot, under the figure() documentation:

If you are creating many figures, make sure you explicitly call
    `.pyplot.close` on the figures you are not using, because this will
    enable pyplot to properly clean up the memory.

So, as others have said, use plt.close() on each figure when you’re done with it, and you’ll be good to go!

NOTE: if you create the figure via f = plt.figure(), you can close it via plt.close( f ) instead of f.close().

Answered By: jvriesem

Answer 8

Did you try plt.close()? that worked for me and made sure I didn’t accidentally save the same plot multiple times.

Code:

def save_to(root: Path, plot_name: str = 'plot', close: bool = True):
    """
    Assuming there is a plot in display, saves it to local users desktop users desktop as a png, svg & pdf.

    note:
        - ref on closing figs after saving: https://stackoverflow.com/questions/741877/how-do-i-tell-matplotlib-that-i-am-done-with-a-plot
        - clf vs cla https://stackoverflow.com/questions/16661790/difference-between-plt-close-and-plt-clf
    """
    root: Path = root.expanduser()
    plt.savefig(root / f'{plot_name}.png')
    plt.savefig(root / f'{plot_name}.svg')
    plt.savefig(root / f'{plot_name}.pdf')
    if close:
        # plt.clf()
        # plt.cla()
        plt.close()

in my ultimate utils lib: https://github.com/brando90/ultimate-utils

Answered By: Charlie Parker

How do I tell matplotlib that I am done with a plot?

Question:

Answers: