如何在php中将对象数组转换为该对象的单个属性的数组？

Question

Say I have an array of Person objects and the person objects have properties firstName, lastName, and age. Now suppose I want an array of the firstnames of all these person objects. How can I convert this array of Person objects into an array of firstname strings?

Is there some combination of array functions I can use to do it or do I just have use a for loop and create a new array?

Answer 1

You can use array_map

    class Person
{
    public $firstName ;
    public $lastName ;
    public $age ;

    function __construct($firstName,$lastName,$age)
    {
        $this->firstName = $firstName ;
        $this->lastName = $lastName ;
        $this->age = $age ;
    }
}

$list = array();
$list[] = new Person("John", "Smith", 22);
$list[] = new Person("Jon", "Doe", 19);
$list[] = new Person("Jane", "Stack", 21);

$lastNames = array_map(function($var){return $var->lastName ; } ,$list);
var_dump($lastNames);

Output

array
  0 => string 'Smith' (length=5)
  1 => string 'Doe' (length=3)
  2 => string 'Stack' (length=5)