pd.set_option('precision', 2)

> df = pd.DataFrame(np.random.random([3, 3]),
...  columns=['A', 'B', 'C'], index=['first', 'second', 'third'])
> df
    A   B   C
first 0.028208 0.992815 0.173891
second 0.038683 0.645646 0.577595
third 0.877076 0.149370 0.491027
> df.round(2)
   A  B  C
first 0.03 0.99 0.17
second 0.04 0.65 0.58
third 0.88 0.15 0.49
> df.round({'A': 1, 'C': 2})
   A   B  C
first 0.0 0.992815 0.17
second 0.0 0.645646 0.58
third 0.9 0.149370 0.49
> decimals = pd.Series([1, 0, 2], index=['A', 'B', 'C'])
> df.round(decimals)
   A B  C
first 0.0 1 0.17
second 0.0 1 0.58
third 0.9 0 0.49