How to create correlation matrix but with only part of the rows?

Question

I would like to have correlation matrix like this one, but with only 3 bottom rows but all the columns. How can I generate it?

corr = corrdata.corr()
sns.heatmap(corr, mask=np.zeros_like(corr), annot=True, cmap=sns.diverging_palette(220, 10, as_cmap=True),
            square=True, ax=ax, fmt='.2f' ,  )