datatable.prod()

Added in version 1.1.0

Calculate the product of values for each column from cols. The product of missing values is calculated as one.

Parameters

cols
FExpr

Input columns.

return
Expr

f-expression having one row, and the same names and number of columns as in cols. The column stypes are int64 for boolean and integer columns, float32 for float32 columns and float64 for float64 columns.

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, prod DT = dt.Frame({'A': [1, 1, 2, 1, 2], 'B': [None, 2, 3, 4, 5], 'C': [1, 2, 1, 1, 2]}) DT
ABC
int32int32int32
01NA1
1122
2231
3141
4252

Get the product for column A:

DT[:, prod(f.A)]
A
int64
04

Get the product for multiple columns:

DT[:, prod(f['A', 'B'])]
AB
int64int64
04120

In the presence of by(), it returns the product of the specified columns per group:

DT[:, prod(f['A', 'B']), by('C')]
CAB
int32int64int64
01212
12210