Hi Astha,
Thanks for showing your interest in this article.
This pictorial representation represents the correlation between the same column itself like num_preg with num_preg, etc. To understand better we have the following patterns as per the plotted graph, just follow the yellow color in the graph:
num_preg->num_preg
glucose_conc->glucose_conc
diastolic_bp->diastolic_bp
thickness->thickness
thickness->skin (correlation doesn’t match as columns differ)
insulin->insulin
bmi->bmi
diab_pred->diab_pred
age->age
skin->thickness (correlation doesn’t match as columns differ)
skin->skin
diabetes->diabetes
Hence, we talked about removing either skin or thickness column.
The same applies to the table:
It is just the numerical representation of the graph. And the values have been calculated by .corr() function which is the part of pandas library.