What does {:.{}f} do?

Question

X = 100.1205
Y = str(X)[6]
print('{:.{}f}'.format(X,Y)
#100

Answer 1

The outer pair of {} refers to X, the inner pair refers to Y. Y = str(X)[6] = 0, so it's the same as {:.0f} which means "show the number with 0 decimal places"

Answer 2

Thanks! Anna