how to accept multiple parameters from returning function in groovy

Question

I want to return multiple values from a function written in groovy and receive them , but i am getting an error

class org.codehaus.groovy.ast.expr.ListExpression, with its value '[a, b]', is a bad expression as the left hand side of an assignment operator

My code is

int a=10 int b=0 println "a is ${a} , b is ${b}" [a,b]=f1(a) println "a is NOW ${a} , b is NOW ${b}"  def f1(int x) {      return [a*10,a*20] } 

Answer 1

You almost have it. Conceptually [ a, b ] creates a list, and ( a, b ) unwraps one, so you want (a,b)=f1(a) instead of [a,b]=f1(a).

int a=10 int b=0 println "a is ${a} , b is ${b}" (a,b)=f1(a) println "a is NOW ${a} , b is NOW ${b}"  def f1(int x) {     return [x*10,x*20] } 

Another example returning objects, which don't need to be the same type:

final Date foo final String bar (foo, bar) = baz() println foo println bar  def baz() {     return [ new Date(0), 'Test' ] } 

Additionally you can combine the declaration and assignment:

final def (Date foo, String bar) = baz() println foo println bar  def baz() {     return [ new Date(0), 'Test' ] } 

Answer 2

You can declare and assign the variables in which the return values are stored in one line like this, which is a slightly more compact syntax than that used in Justin's answer:

def (int a, int b) = f1(22) 

In your particular case you may not be able to use this because one of the variables passed to f1 is also used to store a return value