The Collection interface

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Introduction

Collection is the base interface which covers functionality common to all the data structures in this library. It guarantees that all structures are traversable, countable, and can be converted to json using json_encode().

Interface synopsis

Ds\Collection implements Traversable , Countable , JsonSerializable {
/* Methods */
abstract public clear(): void
abstract public copy(): Ds\Collection
abstract public isEmpty(): bool
abstract public toArray(): array
}

Table of Contents

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depakin at yisangwu dot com
4 years ago
// Collection
   $collection_a = new \Ds\Vector([1, 2, 3]);
   $collection_b = new \Ds\Vector();

   var_dump($collection_a, $collection_b);
    /*
        object(Ds\Vector)[1]
        public 0 => int 1
        public 1 => int 2
        public 2 => int 3

        object(Ds\Vector)[2]
    */

   //json_encode
   var_dump( json_encode($collection_a));
    /*
    string '[1,2,3]
    */
  
    //count
   var_dump(count($collection_a));
    /*
    int 3
    */
  
    // serialize
    var_dump(serialize($collection_a));
    /*
    string 'C:9:"Ds\Vector":12:{i:1;i:2;i:3;}'
    */

    // foreach
    foreach ($collection_a as $key => $value) {
       echo $key ,'--', $value, PHP_EOL;
    }
    /*
       0--1
       1--2
       2--3
     */

    // clone
    $clone = clone($collection_a);
    var_dump($clone);
    /*
      object(Ds\Vector)[1]
      public 0 => int 1
      public 1 => int 2
      public 2 => int 3
    */

    // push
    $clone->push('aa');
    var_dump($clone);
    /*
    object(Ds\Vector)[3]
      public 0 => int 1
      public 1 => int 2
      public 2 => int 3
      public 3 => string 'aa' (length=2)
     */

   // isEmpty
   var_dump($collection_a->isEmpty(), $collection_b->isEmpty());
    /*
    boolean false
    boolean true
     */

   // toArray
   var_dump($collection_a->toArray(), $collection_b->toArray());
    /*
     array (size=3)
      0 => int 1
      1 => int 2
      2 => int 3

    array (size=0)
      empty
    */

   // copy ( void )
   //浅拷贝, shallow copy
   $collection_c = $collection_a->copy();

   var_dump($collection_c);
    /*
    object(Ds\Vector)[3]
      public 0 => int 1
      public 1 => int 2
      public 2 => int 3
    */

   $collection_c->push(4);
   var_dump($collection_a, $collection_c);
    /*
    object(Ds\Vector)[1]
      public 0 => int 1
      public 1 => int 2
      public 2 => int 3

    object(Ds\Vector)[3]
      public 0 => int 1
      public 1 => int 2
      public 2 => int 3
      public 3 => int 4
    */
  
    // clear
    $collection_a->clear();
    $collection_b->clear();
    $collection_c->clear();

    var_dump($collection_a, $collection_b, $collection_c);
    /*
    object(Ds\Vector)[1]
    object(Ds\Vector)[2]
    object(Ds\Vector)[3]
    */
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