Display Chinese characters vertically in the right way in Matplotlib

vertical-chinese

# use index values, which are all Chinese characteres, as x labels, 
# but not enought space to display, so we need to display the characters vertically,
# not jsut rotate x lables
# but to display the characters one at each line.
# reference & courtesy: https://blog.csdn.net/ai_clay/article/details/126038824

df_new=df_filtered.index # get the index values from the original df

df_new= df_new.map(lambda x: '\n'.join(x)) # one character each line

ax.set_xticklabels(df_new.tolist(), rotation=0, verticalalignment='center') ## Set x-axis labels


# Show the plot
plt.show()