array_column

(PHP 5 >= 5.5.0, PHP 7)

array_columnReturn the values from a single column in the input array

Beschreibung

array_column ( array $input , mixed $column_key [, mixed $index_key = NULL ] ) : array

array_column() returns the values from a single column of the input, identified by the column_key. Optionally, an index_key may be provided to index the values in the returned array by the values from the index_key column of the input array.

Parameter-Liste

input

A multi-dimensional array or an array of objects from which to pull a column of values from. If an array of objects is provided, then public properties can be directly pulled. In order for protected or private properties to be pulled, the class must implement both the __get() and __isset() magic methods.

column_key

The column of values to return. This value may be an integer key of the column you wish to retrieve, or it may be a string key name for an associative array or property name. It may also be NULL to return complete arrays or objects (this is useful together with index_key to reindex the array).

index_key

The column to use as the index/keys for the returned array. This value may be the integer key of the column, or it may be the string key name. The value is cast as usual for array keys (however, objects supporting conversion to string are also allowed).

Rückgabewerte

Returns an array of values representing a single column from the input array.

Changelog

Version Beschreibung
7.0.0 Added the ability for the input parameter to be an array of objects.

Beispiele

Beispiel #1 Get the column of first names from a recordset

<?php
// Array representing a possible record set returned from a database
$records = array(
    array(
        
'id' => 2135,
        
'first_name' => 'John',
        
'last_name' => 'Doe',
    ),
    array(
        
'id' => 3245,
        
'first_name' => 'Sally',
        
'last_name' => 'Smith',
    ),
    array(
        
'id' => 5342,
        
'first_name' => 'Jane',
        
'last_name' => 'Jones',
    ),
    array(
        
'id' => 5623,
        
'first_name' => 'Peter',
        
'last_name' => 'Doe',
    )
);
 
$first_names array_column($records'first_name');
print_r($first_names);
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

Array
(
    [0] => John
    [1] => Sally
    [2] => Jane
    [3] => Peter
)

Beispiel #2 Get the column of last names from a recordset, indexed by the "id" column

<?php
// Using the $records array from Example #1
$last_names array_column($records'last_name''id');
print_r($last_names);
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

Array
(
    [2135] => Doe
    [3245] => Smith
    [5342] => Jones
    [5623] => Doe
)

Beispiel #3 Get the column of usernames from the public "username" property of an object

<?php

class User
{
    public 
$username;

    public function 
__construct(string $username)
    {
        
$this->username $username;
    }
}

$users = [
    new 
User('user 1'),
    new 
User('user 2'),
    new 
User('user 3'),
];

print_r(array_column($users'username'));
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

Array
(
    [0] => user 1
    [1] => user 2
    [2] => user 3
)

Beispiel #4 Get the column of names from the private "name" property of an object using the magic __get() method.

<?php

class Person
{
    private 
$name;

    public function 
__construct(string $name)
    {
        
$this->name $name;
    }

    public function 
__get($prop)
    {
        return 
$this->$prop;
    }

    public function 
__isset($prop) : bool
    
{
        return isset(
$this->$prop);
    }
}

$people = [
    new 
Person('Fred'),
    new 
Person('Jane'),
    new 
Person('John'),
];

print_r(array_column($people'name'));
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

Array
(
    [0] => Fred
    [1] => Jane
    [2] => John
)
If __isset() is not provided, then an empty array will be returned.