Scala学习:breakable

一、案例分析

//字符串匹配的BF算法

package Match

import scala.util.control.Breaks._

class BF {
    
  def bfmatch(main:Array[Char],sub:Array[Char]): Int ={
    
    require(main != null, "main array required")
    require(sub != null, "sub array required")
    require(main.length >= sub.length, "sub array should be small than main array")

    var result = -1
    breakable{
    
      for (i <- 0 to (main.length - sub.length)){
    
     //slice字符串截取,左闭右开,[0,2)
        if (main.slice(i,i + sub.length) sameElements sub){
    
          result = i
          break
        }
      }
    }
    result
  }
}

object test{
    
  def main(args:Array[String]): Unit ={
    
    val bf = new BF
    var str1 = "heldfsfslo".toCharArray
    var str2 = "lo".toCharArray
    println(bf.bfmatch(str1,str2))
  }
}

二、breakable用法

• scala没有提供Java中类似的break和continue操作,可以用其它方式实现
• 首先需要导入scala.util.control.Break._这个包,其次将需要控制的结构放入breakable{}代码块中,如上述所示就为break用法

      for (i <- 0 to (main.length - sub.length)){
    
      	breakable{
    
      		if (main.slice(i,i + sub.length) sameElements sub){
    
          		result = i
          		break
        	}
      	}
      }

如上述所示,若breakable{}在for循环中,就为continue用法