​

Select a table column

Select a specific table column using a Table Column expression.

import vitalx.aggregation as va

va.select(va.Sleep.col("efficiency"))

​

Perform an analysis and select the output value

Perform data analysis with in-built algorithms using value macro expressions:

• Sleep Analysis value macro expressions

import vitalx.aggregation as va

va.select(va.Sleep.chronotype())

​

Aggregate a table column

Aggregate a Table Column expression with respect to the group_by clause.

The specified aggregate function is applied to each and every group created by the group_by clause. The result set is N aggregated values where N is the number of groups.

import vitalx.aggregation as va

va.select(
    va.Sleep.col("stage_asleep_second").newest()
)

​

Select the Index Column

Select the primary datetime index of the table using the Index Column expression.

import vitalx.aggregation as va

va.select(va.Sleep.col("efficiency"))

​

Select the Group Key Columns

Select the Group Key Columns associated with the group_by clause.

You can select one specific group key column by offset, or select all group key columns with a * wildcard.

import vitalx.aggregation as va

# Select all group key columns
va.select(va.group_key("*"))

# Select the 2nd group key column
va.select(va.group_key(2))