scala入门初级代码训练-34List的应用函数

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原文地址： http://www.ptbird.cn/2016/07/19/scala-chuji-demo-34/ ‎
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by postbird
www.ptbird.cn


package com.ptbird.scala

/**
  * Created by postbird on 2016/5/26.
  */
object ListTest5 {
  def main(args: Array[String]): Unit = {
    val l = List(1, 2, 3, 4, 5, 6)
    println(l partition (_ % 2 == 0))
    println(l find (_ % 2 == 0)) //第一个
    println(l find (_ <= 0))
    println(l takeWhile (_ < 4)) //所有符合条件的元素
    println(l dropWhile (_ < 4))
    println(l span (_ < 4))
    //    (List(2, 4, 6),List(1, 3, 5))
    //    Some(2)
    //    None
    //    List(1, 2, 3)
    //    List(4, 5, 6)
    //    (List(1, 2, 3),List(4, 5, 6))

    def hastotallyZeroRow(m: List[List[Int]]) = m exists (
      row => row forall (_ == 0) //需要全部满足这个函数 List(0, 0, 0)符合
      )
    val m = List(List(0, 1, 0, 0), List(0, 1, 0), List(0, 0, 0))
    println(hastotallyZeroRow(m))

    //    true
  }
}

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