Scala Self-Study Diary (6)-array initialization and looping

The array inside the 1.scala is similar to that in Java, but there are some different ways of initializing the array, which is a bit more than Java, as follows:

The code is as follows:

Package Com.scala.demo

/**
 * Here is the main introduction to the use of the array
/object ArrayDemo2 {
  val array=new Array[int] (3)
  Val array2=new Array[int] (3)
  Val array3=new Array[int] (3)
  /**
   * Array Assignment operation 1
  /def init1 ()
  { Array
    (0) =1
    Array (1) =2
    Array (2) =3
  }
  /**
   * Array copy operation 2
  /def init2 ()
  {
    array2.update (0,4)
    array2.update (1,5)
    array2.update (2,6)
  }
  /**
   * OUTPUT data *
   *
  def out (Array:array[int])
  {
    val length=array.length
    for (i<-0 to Length-1)  //Note here I cycle
      println (array.apply (i))// Array.apply (i) ==array (i)
  }
  def main (args:array[string])
  {out
    (array3)
    init1 ()
    out (array)
    Init2 () out
    (array2)
  }
}

From the example code above, we can see that there are 2 ways to initialize an array:

One is:

    Array (0) =1
    Array (1) =2
    Array (2) =3

In Scala, things are objects, and arrays are no exception. Array assignment is actually done by a method.

The code above will be converted to two parameters by the compiler, which is the second method:

    Array2.update (0,4)
    array2.update (1,5)
    array2.update (2,6)

Notice how the above loops

The For loop here uses 0 to Length-1

, it is easy to understand that from 0 to length, the default step into 1.

When the method argument is only one, the parentheses and points are not written.

The complete formulation should be:

I<-0.to (length-1)

2. Cycle

Package Com.scala.demo/**  * mainly introduces the way of loops  */object ArrayDemo1 { //var a:array[int]={1;2;3;4;5;6;7;8;9}   /**    * use while    */  def ergodic1 (Array:array[int)) {    println ("Ergodic1
run! ")     var i = 0     while (I < array.length) {      println (Array (i))     & nbsp i++ or ==i can not be used in i+=1//scala, only use i+=1 or i=i+1    }  }  /**    * use the foreach   Java5 inside &N bsp;*/  def ergodic2 (Array:array[int]) {    println ("Ergodic2 run!")     Array.foreach (value =
> println (value))//is actually an anonymous method    /or this: Array.foreach (value:int) =>println (value)  }  /**    * uses a compact version of foreach ...    */  def ergodic3 (Array:array[int]) {    println ("E
RGODIC3 run! ")     Array.foreach (println)//Good Concise writing  }  /**    * use for loop try    */  def ERGODIC4 (Array:array[int]) {    println ("Ergodic4 run!")     for (Arg <-array)//for loop writing     {      println (ARG)    }  }   def main (args:array[string]) {    var array=new array[int] (3)     Array (0) =1     Array (1) =2     Array (2) =3     Ergod IC1 (array)     Ergodic2 (array)     ERGODIC3 (array)     ERGODIC4 (array)  }}