datatable.max()

datatable.

max

(

cols

)

sourcetests

Calculate the maximum value for each column from cols. It is recommended to use it as dt.max() to prevent conflict with the Python built-in max() function.

Parameters

cols

Expr

Input columns.

return

Expr

f-expression having one row and the same names, stypes and number of columns as in cols.

except

TypeError

The exception is raised when one of the columns from cols has a non-numeric type.

Examples

from datatable import dt, f, by df = dt.Frame({'A': [1, 1, 1, 2, 2, 2, 3, 3, 3], 'B': [3, 2, 20, 1, 6, 2, 3, 22, 1]}) df

	A	B
	int32	int32
0	1	3
1	1	2
2	1	20
3	2	1
4	2	6
5	2	2
6	3	3
7	3	22
8	3	1

9 rows × 2 columns

Get the maximum from column B:

df[:, dt.max(f.B)]

	B
	int32
0	22

1 row × 1 column

Get the maximum of all columns:

df[:, [dt.max(f.A), dt.max(f.B)]]

	A	B
	int32	int32
0	3	22

1 row × 2 columns

Same as above, but more convenient:

df[:, dt.max(f[:])]

	A	B
	int32	int32
0	3	22

1 row × 2 columns

In the presence of by(), it returns the row with the maximum value per group:

df[:, dt.max(f.B), by("A")]

	A	B
	int32	int32
0	1	20
1	2	6
2	3	22

3 rows × 2 columns

See Also

• min() – function to calculate minimum values.