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Hash

class Hash

New in version 2.2.

Array management, if done right, can be a very powerful and useful tool for building smarter, more optimized code. CakePHP offers a very useful set of static utilities in the Hash class that allow you to do just that.

CakePHP’s Hash class can be called from any model or controller in the same way Inflector is called. Example: Hash::combine().

Hash path syntax

The path syntax described below is used by all the methods in Hash. Not all parts of the path syntax are available in all methods. A path expression is made of any number of tokens. Tokens are composed of two groups. Expressions, are used to traverse the array data, while matchers are used to qualify elements. You apply matchers to expression elements.

Expression Types

Expression Definition
{n} Represents a numeric key. Will match any string or numeric key.
{s} Represents a string. Will match any string value including numeric string values.
Foo Matches keys with the exact same value.

All expression elements are supported by all methods. In addition to expression elements, you can use attribute matching with certain methods. They are extract(), combine(), format(), check(), map(), reduce(), apply(), sort(), insert(), remove() and nest().

Attribute Matching Types

Matcher Definition
[id] Match elements with a given array key.
[id=2] Match elements with id equal to 2.
[id!=2] Match elements with id not equal to 2.
[id>2] Match elements with id greater than 2.
[id>=2] Match elements with id greater than or equal to 2.
[id<2] Match elements with id less than 2
[id<=2] Match elements with id less than or equal to 2.
[text=/.../] Match elements that have values matching the regular expression inside ....

Changed in version 2.5: Matcher support was added to insert() and remove().

static Hash::get(array $data, $path)
Return type:mixed

get() is a simplified version of extract(), it only supports direct path expressions. Paths with {n}, {s} or matchers are not supported. Use get() when you want exactly one value out of an array.

static Hash::extract(array $data, $path)
Return type:array

Hash::extract() supports all expression, and matcher components of Hash path syntax. You can use extract to retrieve data from arrays, along arbitrary paths quickly without having to loop through the data structures. Instead you use path expressions to qualify which elements you want returned

// Common Usage:
$users = $this->User->find("all");
$results = Hash::extract($users, '{n}.User.id');
// $results equals:
// array(1,2,3,4,5,...);
static Hash::insert(array $data, $path, $values = null)
Return type:array

Inserts $data into an array as defined by $path:

$a = array(
    'pages' => array('name' => 'page')
);
$result = Hash::insert($a, 'files', array('name' => 'files'));
// $result now looks like:
Array
(
    [pages] => Array
        (
            [name] => page
        )
    [files] => Array
        (
            [name] => files
        )
)

You can use paths using {n} and {s} to insert data into multiple points:

$users = $this->User->find('all');
$users = Hash::insert($users, '{n}.User.new', 'value');

Changed in version 2.5: As of 2.5.0 attribute matching expressions work with insert().

static Hash::remove(array $data, $path = null)
Return type:array

Removes all elements from an array that match $path.:

$a = array(
    'pages' => array('name' => 'page'),
    'files' => array('name' => 'files')
);
$result = Hash::remove($a, 'files');
/* $result now looks like:
    Array
    (
        [pages] => Array
            (
                [name] => page
            )

    )
*/

Using {n} and {s} will allow you to remove multiple values at once.

Changed in version 2.5: As of 2.5.0 attribute matching expressions work with remove()

static Hash::combine(array $data, $keyPath = null, $valuePath = null, $groupPath = null)
Return type:array

Creates an associative array using a $keyPath as the path to build its keys, and optionally $valuePath as path to get the values. If $valuePath is not specified, or doesn’t match anything, values will be initialized to null. You can optionally group the values by what is obtained when following the path specified in $groupPath.:

$a = array(
    array(
        'User' => array(
            'id' => 2,
            'group_id' => 1,
            'Data' => array(
                'user' => 'mariano.iglesias',
                'name' => 'Mariano Iglesias'
            )
        )
    ),
    array(
        'User' => array(
            'id' => 14,
            'group_id' => 2,
            'Data' => array(
                'user' => 'phpnut',
                'name' => 'Larry E. Masters'
            )
        )
    ),
);

$result = Hash::combine($a, '{n}.User.id');
/* $result now looks like:
    Array
    (
        [2] =>
        [14] =>
    )
*/

$result = Hash::combine($a, '{n}.User.id', '{n}.User.Data');
/* $result now looks like:
    Array
    (
        [2] => Array
            (
                [user] => mariano.iglesias
                [name] => Mariano Iglesias
            )
        [14] => Array
            (
                [user] => phpnut
                [name] => Larry E. Masters
            )
    )
*/

$result = Hash::combine($a, '{n}.User.id', '{n}.User.Data.name');
/* $result now looks like:
    Array
    (
        [2] => Mariano Iglesias
        [14] => Larry E. Masters
    )
*/

$result = Hash::combine($a, '{n}.User.id', '{n}.User.Data', '{n}.User.group_id');
/* $result now looks like:
    Array
    (
        [1] => Array
            (
                [2] => Array
                    (
                        [user] => mariano.iglesias
                        [name] => Mariano Iglesias
                    )
            )
        [2] => Array
            (
                [14] => Array
                    (
                        [user] => phpnut
                        [name] => Larry E. Masters
                    )
            )
    )
*/

$result = Hash::combine($a, '{n}.User.id', '{n}.User.Data.name', '{n}.User.group_id');
/* $result now looks like:
    Array
    (
        [1] => Array
            (
                [2] => Mariano Iglesias
            )
        [2] => Array
            (
                [14] => Larry E. Masters
            )
    )
*/

You can provide array’s for both $keyPath and $valuePath. If you do this, the first value will be used as a format string, for values extracted by the other paths:

$result = Hash::combine(
    $a,
    '{n}.User.id',
    array('%s: %s', '{n}.User.Data.user', '{n}.User.Data.name'),
    '{n}.User.group_id'
);
/* $result now looks like:
    Array
    (
        [1] => Array
            (
                [2] => mariano.iglesias: Mariano Iglesias
            )
        [2] => Array
            (
                [14] => phpnut: Larry E. Masters
            )
    )
*/

$result = Hash::combine(
    $a,
    array('%s: %s', '{n}.User.Data.user', '{n}.User.Data.name'),
    '{n}.User.id'
);
/* $result now looks like:
    Array
    (
        [mariano.iglesias: Mariano Iglesias] => 2
        [phpnut: Larry E. Masters] => 14
    )
*/
static Hash::format(array $data, array $paths, $format)
Return type:array

Returns a series of values extracted from an array, formatted with a format string:

$data = array(
    array(
        'Person' => array(
            'first_name' => 'Nate',
            'last_name' => 'Abele',
            'city' => 'Boston',
            'state' => 'MA',
            'something' => '42'
        )
    ),
    array(
        'Person' => array(
            'first_name' => 'Larry',
            'last_name' => 'Masters',
            'city' => 'Boondock',
            'state' => 'TN',
            'something' => '{0}'
        )
    ),
    array(
        'Person' => array(
            'first_name' => 'Garrett',
            'last_name' => 'Woodworth',
            'city' => 'Venice Beach',
            'state' => 'CA',
            'something' => '{1}'
        )
    )
);

$res = Hash::format($data, array('{n}.Person.first_name', '{n}.Person.something'), '%2$d, %1$s');
/*
Array
(
    [0] => 42, Nate
    [1] => 0, Larry
    [2] => 0, Garrett
)
*/

$res = Hash::format($data, array('{n}.Person.first_name', '{n}.Person.something'), '%1$s, %2$d');
/*
Array
(
    [0] => Nate, 42
    [1] => Larry, 0
    [2] => Garrett, 0
)
*/
static Hash::contains(array $data, array $needle)
Return type:boolean

Determines if one Hash or array contains the exact keys and values of another:

$a = array(
    0 => array('name' => 'main'),
    1 => array('name' => 'about')
);
$b = array(
    0 => array('name' => 'main'),
    1 => array('name' => 'about'),
    2 => array('name' => 'contact'),
    'a' => 'b'
);

$result = Hash::contains($a, $a);
// true
$result = Hash::contains($a, $b);
// false
$result = Hash::contains($b, $a);
// true
static Hash::check(array $data, string $path = null)
Return type:boolean

Checks if a particular path is set in an array:

$set = array(
    'My Index 1' => array('First' => 'The first item')
);
$result = Hash::check($set, 'My Index 1.First');
// $result == True

$result = Hash::check($set, 'My Index 1');
// $result == True

$set = array(
    'My Index 1' => array('First' =>
        array('Second' =>
            array('Third' =>
                array('Fourth' => 'Heavy. Nesting.'))))
);
$result = Hash::check($set, 'My Index 1.First.Second');
// $result == True

$result = Hash::check($set, 'My Index 1.First.Second.Third');
// $result == True

$result = Hash::check($set, 'My Index 1.First.Second.Third.Fourth');
// $result == True

$result = Hash::check($set, 'My Index 1.First.Seconds.Third.Fourth');
// $result == False
static Hash::filter(array $data, $callback = array('Hash', 'filter'))
Return type:array

Filters empty elements out of array, excluding ‘0’. You can also supply a custom $callback to filter the array elements. You callback should return false to remove elements from the resulting array:

$data = array(
    '0',
    false,
    true,
    0,
    array('one thing', 'I can tell you', 'is you got to be', false)
);
$res = Hash::filter($data);

/* $data now looks like:
    Array (
        [0] => 0
        [2] => true
        [3] => 0
        [4] => Array
            (
                [0] => one thing
                [1] => I can tell you
                [2] => is you got to be
            )
    )
*/
static Hash::flatten(array $data, string $separator = '.')
Return type:array

Collapses a multi-dimensional array into a single dimension:

$arr = array(
    array(
        'Post' => array('id' => '1', 'title' => 'First Post'),
        'Author' => array('id' => '1', 'user' => 'Kyle'),
    ),
    array(
        'Post' => array('id' => '2', 'title' => 'Second Post'),
        'Author' => array('id' => '3', 'user' => 'Crystal'),
    ),
);
$res = Hash::flatten($arr);
/* $res now looks like:
    Array (
        [0.Post.id] => 1
        [0.Post.title] => First Post
        [0.Author.id] => 1
        [0.Author.user] => Kyle
        [1.Post.id] => 2
        [1.Post.title] => Second Post
        [1.Author.id] => 3
        [1.Author.user] => Crystal
    )
*/
static Hash::expand(array $data, string $separator = '.')
Return type:array

Expands an array that was previously flattened with Hash::flatten():

$data = array(
    '0.Post.id' => 1,
    '0.Post.title' => First Post,
    '0.Author.id' => 1,
    '0.Author.user' => Kyle,
    '1.Post.id' => 2,
    '1.Post.title' => Second Post,
    '1.Author.id' => 3,
    '1.Author.user' => Crystal,
);
$res = Hash::expand($data);
/* $res now looks like:
array(
    array(
        'Post' => array('id' => '1', 'title' => 'First Post'),
        'Author' => array('id' => '1', 'user' => 'Kyle'),
    ),
    array(
        'Post' => array('id' => '2', 'title' => 'Second Post'),
        'Author' => array('id' => '3', 'user' => 'Crystal'),
    ),
);
*/
static Hash::merge(array $data, array $merge[, array $n])
Return type:array

This function can be thought of as a hybrid between PHP’s array_merge and array_merge_recursive. The difference to the two is that if an array key contains another array then the function behaves recursive (unlike array_merge) but does not do if for keys containing strings (unlike array_merge_recursive).

Note

This function will work with an unlimited amount of arguments and typecasts non-array parameters into arrays.

$array = array(
    array(
        'id' => '48c2570e-dfa8-4c32-a35e-0d71cbdd56cb',
        'name' => 'mysql raleigh-workshop-08 < 2008-09-05.sql ',
        'description' => 'Importing an sql dump'
    ),
    array(
        'id' => '48c257a8-cf7c-4af2-ac2f-114ecbdd56cb',
        'name' => 'pbpaste | grep -i Unpaid | pbcopy',
        'description' => 'Remove all lines that say "Unpaid".',
    )
);
$arrayB = 4;
$arrayC = array(0 => "test array", "cats" => "dogs", "people" => 1267);
$arrayD = array("cats" => "felines", "dog" => "angry");
$res = Hash::merge($array, $arrayB, $arrayC, $arrayD);

/* $res now looks like:
Array
(
    [0] => Array
        (
            [id] => 48c2570e-dfa8-4c32-a35e-0d71cbdd56cb
            [name] => mysql raleigh-workshop-08 < 2008-09-05.sql
            [description] => Importing an sql dump
        )
    [1] => Array
        (
            [id] => 48c257a8-cf7c-4af2-ac2f-114ecbdd56cb
            [name] => pbpaste | grep -i Unpaid | pbcopy
            [description] => Remove all lines that say "Unpaid".
        )
    [2] => 4
    [3] => test array
    [cats] => felines
    [people] => 1267
    [dog] => angry
)
*/
static Hash::numeric(array $data)
Return type:boolean

Checks to see if all the values in the array are numeric:

$data = array('one');
$res = Hash::numeric(array_keys($data));
// $res is true

$data = array(1 => 'one');
$res = Hash::numeric($data);
// $res is false
static Hash::dimensions(array $data)
Return type:integer

Counts the dimensions of an array. This method will only consider the dimension of the first element in the array:

$data = array('one', '2', 'three');
$result = Hash::dimensions($data);
// $result == 1

$data = array('1' => '1.1', '2', '3');
$result = Hash::dimensions($data);
// $result == 1

$data = array('1' => array('1.1' => '1.1.1'), '2', '3' => array('3.1' => '3.1.1'));
$result = Hash::dimensions($data);
// $result == 2

$data = array('1' => '1.1', '2', '3' => array('3.1' => '3.1.1'));
$result = Hash::dimensions($data);
// $result == 1

$data = array('1' => array('1.1' => '1.1.1'), '2', '3' => array('3.1' => array('3.1.1' => '3.1.1.1')));
$result = Hash::dimensions($data);
// $result == 2
static Hash::maxDimensions(array $data)

Similar to dimensions(), however this method returns, the deepest number of dimensions of any element in the array:

$data = array('1' => '1.1', '2', '3' => array('3.1' => '3.1.1'));
$result = Hash::maxDimensions($data, true);
// $result == 2

$data = array('1' => array('1.1' => '1.1.1'), '2', '3' => array('3.1' => array('3.1.1' => '3.1.1.1')));
$result = Hash::maxDimensions($data, true);
// $result == 3
static Hash::map(array $data, $path, $function)

Creates a new array, by extracting $path, and mapping $function across the results. You can use both expression and matching elements with this method:

//call the noop function $this->noop() on every element of $data
$result = Hash::map($data, "{n}", array($this, 'noop'));

function noop($array) {
 //do stuff to array and return the result
 return $array;
}
static Hash::reduce(array $data, $path, $function)

Creates a single value, by extracting $path, and reducing the extracted results with $function. You can use both expression and matching elements with this method.

static Hash::apply(array $data, $path, $function)

Apply a callback to a set of extracted values using $function. The function will get the extracted values as the first argument.

static Hash::sort(array $data, $path, $dir, $type = 'regular')
Return type:array

Sorts an array by any value, determined by a Hash path syntax Only expression elements are supported by this method:

$a = array(
    0 => array('Person' => array('name' => 'Jeff')),
    1 => array('Shirt' => array('color' => 'black'))
);
$result = Hash::sort($a, '{n}.Person.name', 'asc');
/* $result now looks like:
    Array
    (
        [0] => Array
            (
                [Shirt] => Array
                    (
                        [color] => black
                    )
            )
        [1] => Array
            (
                [Person] => Array
                    (
                        [name] => Jeff
                    )
            )
    )
*/

$dir can be either asc or desc. $type can be one of the following values:

  • regular for regular sorting.
  • numeric for sorting values as their numeric equivalents.
  • string for sorting values as their string value.
  • natural for sorting values in a human friendly way. Will sort foo10 below foo2 as an example. Natural sorting requires PHP 5.4 or greater.
static Hash::diff(array $data, array $compare)
Return type:array

Computes the difference between two arrays:

$a = array(
    0 => array('name' => 'main'),
    1 => array('name' => 'about')
);
$b = array(
    0 => array('name' => 'main'),
    1 => array('name' => 'about'),
    2 => array('name' => 'contact')
);

$result = Hash::diff($a, $b);
/* $result now looks like:
    Array
    (
        [2] => Array
            (
                [name] => contact
            )
    )
*/
static Hash::mergeDiff(array $data, array $compare)
Return type:array

This function merges two arrays and pushes the differences in data to the bottom of the resultant array.

Example 1

$array1 = array('ModelOne' => array('id' => 1001, 'field_one' => 'a1.m1.f1', 'field_two' => 'a1.m1.f2'));
$array2 = array('ModelOne' => array('id' => 1003, 'field_one' => 'a3.m1.f1', 'field_two' => 'a3.m1.f2', 'field_three' => 'a3.m1.f3'));
$res = Hash::mergeDiff($array1, $array2);

/* $res now looks like:
    Array
    (
        [ModelOne] => Array
            (
                [id] => 1001
                [field_one] => a1.m1.f1
                [field_two] => a1.m1.f2
                [field_three] => a3.m1.f3
            )
    )
*/

Example 2

$array1 = array("a" => "b", 1 => 20938, "c" => "string");
$array2 = array("b" => "b", 3 => 238, "c" => "string", array("extra_field"));
$res = Hash::mergeDiff($array1, $array2);
/* $res now looks like:
    Array
    (
        [a] => b
        [1] => 20938
        [c] => string
        [b] => b
        [3] => 238
        [4] => Array
            (
                [0] => extra_field
            )
    )
*/
static Hash::normalize(array $data, $assoc = true)
Return type:array

Normalizes an array. If $assoc is true, the resulting array will be normalized to be an associative array. Numeric keys with values, will be converted to string keys with null values. Normalizing an array, makes using the results with Hash::merge() easier:

$a = array('Tree', 'CounterCache',
    'Upload' => array(
        'folder' => 'products',
        'fields' => array('image_1_id', 'image_2_id')
    )
);
$result = Hash::normalize($a);
/* $result now looks like:
    Array
    (
        [Tree] => null
        [CounterCache] => null
        [Upload] => Array
            (
                [folder] => products
                [fields] => Array
                    (
                        [0] => image_1_id
                        [1] => image_2_id
                    )
            )
    )
*/

$b = array(
    'Cacheable' => array('enabled' => false),
    'Limit',
    'Bindable',
    'Validator',
    'Transactional'
);
$result = Hash::normalize($b);
/* $result now looks like:
    Array
    (
        [Cacheable] => Array
            (
                [enabled] => false
            )

        [Limit] => null
        [Bindable] => null
        [Validator] => null
        [Transactional] => null
    )
*/
static Hash::nest(array $data, array $options = array())

Takes a flat array set, and creates a nested, or threaded data structure. Used by methods like Model::find('threaded').

Options:

  • children The key name to use in the result set for children. Defaults to ‘children’.
  • idPath The path to a key that identifies each entry. Should be compatible with Hash::extract(). Defaults to {n}.$alias.id
  • parentPath The path to a key that identifies the parent of each entry. Should be compatible with Hash::extract(). Defaults to {n}.$alias.parent_id
  • root The id of the desired top-most result.

Example:

$data = array(
    array('ModelName' => array('id' => 1, 'parent_id' => null)),
    array('ModelName' => array('id' => 2, 'parent_id' => 1)),
    array('ModelName' => array('id' => 3, 'parent_id' => 1)),
    array('ModelName' => array('id' => 4, 'parent_id' => 1)),
    array('ModelName' => array('id' => 5, 'parent_id' => 1)),
    array('ModelName' => array('id' => 6, 'parent_id' => null)),
    array('ModelName' => array('id' => 7, 'parent_id' => 6)),
    array('ModelName' => array('id' => 8, 'parent_id' => 6)),
    array('ModelName' => array('id' => 9, 'parent_id' => 6)),
    array('ModelName' => array('id' => 10, 'parent_id' => 6))
);

$result = Hash::nest($data, array('root' => 6));
/* $result now looks like:
array(
        (int) 0 => array(
            'ModelName' => array(
                'id' => (int) 6,
                'parent_id' => null
            ),
            'children' => array(
                (int) 0 => array(
                    'ModelName' => array(
                        'id' => (int) 7,
                        'parent_id' => (int) 6
                    ),
                    'children' => array()
                ),
                (int) 1 => array(
                    'ModelName' => array(
                        'id' => (int) 8,
                        'parent_id' => (int) 6
                    ),
                    'children' => array()
                ),
                (int) 2 => array(
                    'ModelName' => array(
                        'id' => (int) 9,
                        'parent_id' => (int) 6
                    ),
                    'children' => array()
                ),
                (int) 3 => array(
                    'ModelName' => array(
                        'id' => (int) 10,
                        'parent_id' => (int) 6
                    ),
                    'children' => array()
                )
            )
        )
    )
    */