df.with { name.firstName }

Input DataFrame: rowsCount = 7, columnsCount = 5

name		age	city	weight	isHappy
firstName	lastName
Alice	Cooper	15	London	54	true
Bob	Dylan	45	Dubai	87	true
Charlie	Daniels	20	Moscow	null	false
Charlie	Chaplin	40	Milan	null	true
Bob	Marley	30	Tokyo	68	true
Alice	Wolf	20	null	55	false
Charlie	Byrd	30	Moscow	90	true

Output DataFrame: rowsCount = 7, columnsCount = 5

firstName	age	city	weight	isHappy
Alice	15	London	54	true
Bob	45	Dubai	87	true
Charlie	20	Moscow	null	false
Charlie	40	Milan	null	true
Bob	30	Tokyo	68	true
Alice	20	null	55	false
Charlie	30	Moscow	90	true

df.with { it.lowercase() }

Input DataFrame: rowsCount = 7, columnsCount = 5

name		age	city	weight	isHappy
firstName	lastName
Alice	Cooper	15	London	54	true
Bob	Dylan	45	Dubai	87	true
Charlie	Daniels	20	Moscow	null	false
Charlie	Chaplin	40	Milan	null	true
Bob	Marley	30	Tokyo	68	true
Alice	Wolf	20	null	55	false
Charlie	Byrd	30	Moscow	90	true

Output DataFrame: rowsCount = 7, columnsCount = 5

name		age	city	weight	isHappy
firstName	lastName
Alice	Cooper	15	london	54	true
Bob	Dylan	45	dubai	87	true
Charlie	Daniels	20	moscow	null	false
Charlie	Chaplin	40	milan	null	true
Bob	Marley	30	tokyo	68	true
Alice	Wolf	20	null	55	false
Charlie	Byrd	30	moscow	90	true

df.with { 2021 - age named "year" }

Input DataFrame: rowsCount = 7, columnsCount = 5

name		age	city	weight	isHappy
firstName	lastName
Alice	Cooper	15	London	54	true
Bob	Dylan	45	Dubai	87	true
Charlie	Daniels	20	Moscow	null	false
Charlie	Chaplin	40	Milan	null	true
Bob	Marley	30	Tokyo	68	true
Alice	Wolf	20	null	55	false
Charlie	Byrd	30	Moscow	90	true

Output DataFrame: rowsCount = 7, columnsCount = 5

name		year	city	weight	isHappy
firstName	lastName
Alice	Cooper	2006	London	54	true
Bob	Dylan	1976	Dubai	87	true
Charlie	Daniels	2001	Moscow	null	false
Charlie	Chaplin	1981	Milan	null	true
Bob	Marley	1991	Tokyo	68	true
Alice	Wolf	2001	null	55	false
Charlie	Byrd	1991	Moscow	90	true