columnGroup

    | [column, ..]

    | [{ condition }]

    | { colsSelector }

    | .allCols()

    | .allCols(Before|After|From|UpTo) ( (column) | { colSelector } )

    | .allColsExcept { colsSelector }

    | .allColsExcept(columnNoAccessor, ..)

    | .and (|{ columnOrSet }|)

    | (.col| .valueCol| .frameCol| .colGroup)[<T>](column | index)

    | (.cols| .valueCols| .frameCols| .colGroups) [ { condition } ]

    | .cols[<T>](column,.. |index,.. |indexRange)

    | .colsAtAnyDepth()

    | .colsInGroups()

    | .colsName(Starts|Ends)With(text[, ignoreCase])

    | .colsNameContains(text[, ignoreCase] | regex)

    | .colsOfKind(kind, ..) [ { condition } ]

    | .colsWithoutNulls()

    | .drop(Last)Cols(number)

    | .drop(Last)ColsWhile { condition }

    | .except { colsSelector }

    | .except(columnNoAccessor, ..)

    | (.firstCol|.lastCol) [ { condition } ]

    | .singleCol()

    | .select { colsSelector }

    | .take(Last)Cols(number)

    | .take(Last)ColsWhile { condition }

singleColumn

    .colsOf<T> [ (kType) ] [ { condition } ]

columnGroupReference

    .colsOf<T>(kType) [ { condition } ]