如何在groovy中接受来自返回函数的多个参数 [英] how to accept multiple parameters from returning function in groovy

问题描述

我想从一个用groovy编写的函数中返回多个值并接收它们，但是我得到一个错误

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，其值'[a，
b]'是一个不好的表达式，因为作业的左手边
操作符

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

我的代码是

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]
}

推荐答案

您几乎拥有它。从概念上讲， [a，b] 会创建一个列表，并且（a，b）展开一个列表，所以您需要（a，b）= f1（a）而不是 [a，b] = f1（a）。

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' ]
}

另外，您可以合并声明和赋值： / p>

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' ]
}

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