python:more than 20 figures have

RuntimeWarning: 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. (To control this warning, see the rcParam figure.max_open_warning).
max_open_warning, RuntimeWarning)

If you intend to knowingly keep many plots in memory, but don't want to be warned about it, you can update your options prior to generating figures.

plt.rcParams.update({'figure.max_open_warning': 0})

plt.cla() # clear a axis
plt.clf()# clear the entire current figure with all its axes, but leaved the window opened, such that it may be reused for other plots;
plt.close()# close the window,which will be the current window,
plt.close('all')will close all open figures
参考网址：https://stackoverflow.com/questions/21884271/warning-about-too-many-open-figures