count_

agg.count_ returns an aggregator that computes the number of elements within an aggregation group.

Note

count is a reserved Python keyword, so an underscore is used to maintain Python conventions.

Syntax

count_(col: str) -> Aggregation

Parameters

Parameter	Type	Description
col	str	The name of the output column that will contain the number of elements in each group.

Returns

An aggregator that computes the number of elements within an aggregation group, for each group.

Examples

In this example, agg.count adds a count column, Number, while agg.avgreturns the average Number, as grouped by X.

from deephaven import new_table
from deephaven.column import string_col, int_col, double_col
from deephaven import agg as agg

source = new_table(
    [
        string_col("X", ["A", "B", "A", "C", "B", "A", "B", "B", "C"]),
        string_col("Y", ["M", "P", "O", "N", "P", "M", "O", "P", "N"]),
        int_col("Number", [55, 76, 20, 130, 230, 50, 73, 137, 214]),
    ]
)

result = source.agg_by(
    [agg.count_(col="Number"), agg.avg(cols="AvgNum = Number")], by=["X"]
)

count_

Syntax

Parameters

Returns

Examples

Related documentation