# How to plot a heatmap-like plot for categorical features?

I would greatly appreciate let me know how to plot a heatmap-like plot for categorical features?

In fact, based on this post, the association between categorical variables should be computed using Crammer's V. Therefore, I found the following code to plot it, but I don't know why he plotted it for "contribution", which is a numeric variable?

def cramers_corrected_stat(confusion_matrix):
""" calculate Cramers V statistic for categorical-categorical association.
uses correction from Bergsma and Wicher,
Journal of the Korean Statistical Society 42 (2013): 323-328
"""
chi2 = ss.chi2_contingency(confusion_matrix)[0]
n = confusion_matrix.sum().sum()
phi2 = chi2/n
r,k = confusion_matrix.shape
phi2corr = max(0, phi2 - ((k-1)*(r-1))/(n-1))
rcorr = r - ((r-1)**2)/(n-1)
kcorr = k - ((k-1)**2)/(n-1)
return np.sqrt(phi2corr / min( (kcorr-1), (rcorr-1)))

cols = ["Party", "Vote", "contrib"]
corrM = np.zeros((len(cols),len(cols)))
# there's probably a nice pandas way to do this
for col1, col2 in itertools.combinations(cols, 2):
idx1, idx2 = cols.index(col1), cols.index(col2)
corrM[idx1, idx2] = cramers_corrected_stat(pd.crosstab(df[col1], df[col2]))
corrM[idx2, idx1] = corrM[idx1, idx2]

corr = pd.DataFrame(corrM, index=cols, columns=cols)
fig, ax = plt.subplots(figsize=(7, 6))
ax = sns.heatmap(corr, annot=True, ax=ax); ax.set_title("Cramer V Correlation between Variables");


I also found Bokeh. However, I am not sure if it uses Crammer's V to plot the heatmap or not?

Really, I have two categorical features: the first one has 2 categories and the second one has 37 categories.

I need the plot will be like the two last plots presented here, but also display the association values on it too.