The Collection interface

(PECL ds >= 1.0.0)

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

interface Ds\Collection extends Countable, IteratorAggregate, JsonSerializable {
/* Methods */
public clear(): void
public isEmpty(): bool
public toArray(): array
/* Inherited methods */
}

Changelog

Version Description
PECL ds 1.4.0 Collection implements IteratorAggregate now instead of just Traversable. (This change came to the polyfill in 1.4.1.)

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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