datatable.max()

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
AB
int32int32
013
112
2120
321
426
522
633
7322
831

Get the maximum from column B:

df[:, dt.max(f.B)]
B
int32
022

Get the maximum of all columns:

df[:, [dt.max(f.A), dt.max(f.B)]]
AB
int32int32
0322

Same as above, but more convenient:

df[:, dt.max(f[:])]
AB
int32int32
0322

You can pass in a dictionary with new column names:

df[:, dt.max({"A_max": f.A, "B_max": f.B})]
A_maxB_max
int32int32
0322

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

df[:, dt.max(f.B), by("A")]
AB
int32int32
0120
126
2322