Is it possible to annotate imshow heatmap the way that if the value from pandas Dataframe is e.g. less than 3, then make mark "x" in that specific heatmap window?

Lets assume I have similar data to this example:

d = {'col1': [1,2,1,5,3], 'col2': [3,4,1,5,2],'col3': [3,4,3,1,2],'col4': [3,4,1,2,5]}
df = pd.DataFrame(data=d)

fig = plt.figure(figsize=(6,4))
plot = plt.imshow(df)
ax = plot.axes
ax.invert_yaxis()
ax.set_xticklabels(df.columns)

I saw that we can annotate all heatmap windows with corresponding values, however I can't figure out how to annotate just the windows below my given limit and not with the corresponding value but e.g. with mark "x". Can I ask for suggestions if it is possible with matplotlib heatmaps, please? Thank you.

CodePudding user response：

• Iterate through the values, and use an if-condition to control adding the text.
• Modified from