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(PHP 4, PHP 5, PHP 7, PHP 8)
array — Create an array
array(mixed ...$values): array
Creates an array. Read the section on the array type for more information on what an array is.
values
Syntax "index => values", separated by commas, define index and values. index may be of type string or integer. When index is omitted, an integer index is automatically generated, starting at 0. If index is an integer, next generated index will be the biggest integer index + 1. Note that when two identical index are defined, the last overwrite the first.
Having a trailing comma after the last defined array entry, while unusual, is a valid syntax.
Returns an array of the parameters. The parameters can be given an index with the
=>
operator. Read the section on the array type for more information on what an array is.
The following example demonstrates how to create a two-dimensional array, how to specify keys for associative arrays, and how to skip-and-continue numeric indices in normal arrays.
Example #1 array() example
<?php
$fruits = array (
"fruits" => array("a" => "orange", "b" => "banana", "c" => "apple"),
"numbers" => array(1, 2, 3, 4, 5, 6),
"holes" => array("first", 5 => "second", "third")
);
?>
Example #2 Automatic index with array()
<?php
$array = array(1, 1, 1, 1, 1, 8 => 1, 4 => 1, 19, 3 => 13);
print_r($array);
?>
The above example will output:
Array
(
[0] => 1
[1] => 1
[2] => 1
[3] => 13
[4] => 1
[8] => 1
[9] => 19
)
Note that index '3' is defined twice, and keep its final value of 13. Index 4 is defined after index 8, and next generated index (value 19) is 9, since biggest index was 8.
This example creates a 1-based array.
Example #3 1-based index with array()
<?php
$firstquarter = array(1 => 'January', 'February', 'March');
print_r($firstquarter);
?>
The above example will output:
Array
(
[1] => January
[2] => February
[3] => March
)
As in Perl, you can access a value from the array inside double quotes. However, with PHP you'll need to enclose your array between curly braces.
Example #4 Accessing an array inside double quotes
<?php
$foo = array('bar' => 'baz');
echo "Hello {$foo['bar']}!"; // Hello baz!
?>
Note :
array() is a language construct used to represent literal arrays, and not a regular function.
(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
array_change_key_case — Changes the case of all keys in an array
array_change_key_case(array $array, int $case = CASE_LOWER): array
Returns an array with all keys from
array
lowercased or uppercased. Numbered indices are left as is.
array
The array to work on
case
Either
CASE_UPPER
or
CASE_LOWER
(default)
Returns an array with its keys lower or uppercased, or
null
if
array
is not an array.
Example #1 array_change_key_case() example
<?php
$input_array = array("FirSt" => 1, "SecOnd" => 4);
print_r(array_change_key_case($input_array, CASE_UPPER));
?>
The above example will output:
Array
(
[FIRST] => 1
[SECOND] => 4
)
Note :
If an array has indices that will be the same once run through this function (e.g. "
keY" and "kEY"), the value that is later in the array will override other indices.
(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
array_chunk — Split an array into chunks
array_chunk(array $array, int $length, bool $preserve_keys = false): array
Chunks an array into arrays with
length
elements. The last chunk may contain less than
length
elements.
array
The array to work on
length
The size of each chunk
preserve_keys
When set to
true
keys will be preserved. Default is
false
which will reindex the chunk numerically
Returns a multidimensional numerically indexed array, starting with zero, with each dimension containing
length
elements.
If
length
is less than
1
, a
ValueError
will be thrown.
| Version | Description |
|---|---|
| 8.0.0 |
If
length
is less than
1
, a
ValueError
will be thrown now; previously, an error of level
E_WARNING
has been raised instead, and the function returned
null
.
|
Example #1 array_chunk() example
<?php
$input_array = array('a', 'b', 'c', 'd', 'e');
print_r(array_chunk($input_array, 2));
print_r(array_chunk($input_array, 2, true));
?>
The above example will output:
Array
(
[0] => Array
(
[0] => a
[1] => b
)
[1] => Array
(
[0] => c
[1] => d
)
[2] => Array
(
[0] => e
)
)
Array
(
[0] => Array
(
[0] => a
[1] => b
)
[1] => Array
(
[2] => c
[3] => d
)
[2] => Array
(
[4] => e
)
)
(PHP 5 >= 5.5.0, PHP 7, PHP 8)
array_column — Return the values from a single column in the input array
array_column(array $array, int|string|null $column_key, int|string|null $index_key = null): array
array_column()
returns the values from a single column of the
array
, 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.
array
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, prior to PHP 8.0.0, objects supporting conversion to string were also allowed).
Returns an array of values representing a single column from the input array.
| Version | Description |
|---|---|
| 8.0.0 |
Objects in columns indicated by
index_key
parameter will no longer be cast to string and will now throw a
TypeError
instead.
|
Example #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);
?>
The above example will output:
Array
(
[0] => John
[1] => Sally
[2] => Jane
[3] => Peter
)
Example #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);
?>
The above example will output:
Array
(
[2135] => Doe
[3245] => Smith
[5342] => Jones
[5623] => Doe
)
Example #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'));
?>
The above example will output:
Array
(
[0] => user 1
[1] => user 2
[2] => user 3
)
Example #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'));
?>
The above example will output:
Array
(
[0] => Fred
[1] => Jane
[2] => John
)
(PHP 5, PHP 7, PHP 8)
array_combine — Creates an array by using one array for keys and another for its values
array_combine(array $keys, array $values): array
Creates an
array
by using the values from the
keys
array as keys and the values from the
values
array as the corresponding values.
keys
Array of keys to be used. Illegal values for key will be converted to string .
values
Array of values to be used
Returns the combined array .
As of PHP 8.0.0, a
ValueError
is thrown if the number of elements in
keys
and
values
does not match. Prior to PHP 8.0.0, a
E_WARNING
was emitted instead.
| Version | Description |
|---|---|
| 8.0.0 |
array_combine()
will now throw a
ValueError
if the number of elements for each array is not equal; previously this function returned
false
instead.
|
Example #1 A simple array_combine() example
<?php
$a = array('green', 'red', 'yellow');
$b = array('avocado', 'apple', 'banana');
$c = array_combine($a, $b);
print_r($c);
?>
The above example will output:
Array
(
[green] => avocado
[red] => apple
[yellow] => banana
)
(PHP 4, PHP 5, PHP 7, PHP 8)
array_count_values — Counts all the values of an array
array_count_values(array $array): array
array_count_values()
returns an array using the values of
array
(which must be
int
s or
string
s) as keys and their frequency in
array
as values.
array
The array of values to count
Returns an associative array of values from
array
as keys and their count as value.
Throws
E_WARNING
for every element which is not
string
or
int
.
Example #1 array_count_values() example
<?php
$array = array(1, "hello", 1, "world", "hello");
print_r(array_count_values($array));
?>
The above example will output:
Array
(
[1] => 2
[hello] => 2
[world] => 1
)