[FIXED] Change certain squares in a seaborn heat map

Issue

Say I have a heat map that looks like this (axes are trimmed off):

I want to be able to alter certain squares to denote statistical significance. I know that I could mask out the squares that are not statistically significant, but I still want to retain that information (and not set the values to zero). Options for doing this include 1) making the text on certain squares bold, 2) adding a hatch-like functionality so that certain squares have stippling, or 3) adding a symbol to certain squares.

What should I do?

Solution

You could plot twice, applying a mask to the cells you do not want to emphasize the second time:

import numpy as np
import seaborn as sns
x = np.random.randn(10, 10)
sns.heatmap(x, annot=True)
sns.heatmap(x, mask=x < 1, cbar=False,
            annot=True, annot_kws={"weight": "bold"})

Answered By - mwaskom