df.select { name named "name2" }

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 = 1

name2
firstName	lastName
Alice	Cooper
Bob	Dylan
Charlie	Daniels
Charlie	Chaplin
Bob	Marley
Alice	Wolf
Charlie	Byrd

df.select { age named "age2" }

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 = 1

age2
15
45
20
40
30
20
30

df.add(df1, df2)

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 = 7

name		age	city	weight	isHappy	name2		age2
firstName	lastName					firstName	lastName
Alice	Cooper	15	London	54	true	Alice	Cooper	15
Bob	Dylan	45	Dubai	87	true	Bob	Dylan	45
Charlie	Daniels	20	Moscow	null	false	Charlie	Daniels	20
Charlie	Chaplin	40	Milan	null	true	Charlie	Chaplin	40
Bob	Marley	30	Tokyo	68	true	Bob	Marley	30
Alice	Wolf	20	null	55	false	Alice	Wolf	20
Charlie	Byrd	30	Moscow	90	true	Charlie	Byrd	30