ColumnsSelectionDslWithExample

Select or express a single column using the Column Selection DSL. (Any Access APIs).

This DSL is initiated by a Column Selector lambda, which operates in context of the Column Selection DSL and expects you to return a SingleColumn. This is an entity formed by calling any (combination) of the functions in the DSL that is or can be resolved into a single column.

The Column Selection DSL allows using Extension Properties for specifying column type- and name-safe.

See Column Selectors on the documentation website.

For example:

df.operation{ length }

df.operation{ col(1) }

df.operation{ colsOf<Double>().first() }