常规列表应用关闭

Question

Simple question. I'm to write a void "apply" which perform Closure on each element of the List.

class Lista {

  def applay(List l, Closure c){
    return l.each(c)
  }

  static main(args) {
    Lista t = new Lista()
    List i = [1,2,3,8,3,2,1]
    Closure c = {it++}
    println t.applay(i, c)
  }
}

Do You have any idea what is wrong with that?

Answer 1

The problem with your code is that the closure {it++} increments every element in the List by 1, but the result is not saved anywhere. I guess what you want to do is create a new List that contains the result of applying this closure to each element of the orginal List. If so, you should use collect instead of each .

class Lista {

  def applay(List l, Closure c){
    return l.collect(c) // I changed this line
  }

  static main(args) {
    Lista t = new Lista()
    List i = [1,2,3,8,3,2,1]
    Closure c = {it + 1} // I changed this line
    println t.applay(i, c)
  }
}

Answer 2

Alternative answer (not so Java-like):

class Lista {
    def apply = { list, closure -> list.collect(closure) }

    def main = {
        println apply([1,2,3,8,3,2,1], {it + 1})
    }
}

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