Working with PHP arrays easily

Easy to use and elegant handling for PHP arrays with an array-like map object as offered by jQuery and Laravel Collections.

composer req aimeos/map

Table of contents

• Why
• List of methods
• Method documentation
• Custom methods
• Performance

Why

Instead of:

$list = [['id' => 'one', 'value' => 'value1'], ['id' => 'two', 'value' => 'value2'], null];
$list[] = ['id' => 'three', 'value' => 'value3'];    // add element
unset( $list[0] );                                   // remove element
$list = array_filter( $list );                       // remove empty values
sort( $list );                                       // sort elements
$pairs = array_column( $list, 'value', 'id' );       // create ['three' => 'value3']
$value = reset( $pairs ) ?: null;                    // return first value

Only use:

$list = [['id' => 'one', 'value' => 'value1'], ['id' => 'two', 'value' => 'value2'], null];
$value = map( $list )                                // create Map
    ->push( ['id' => 'three', 'value' => 'value3'] ) // add element
    ->remove( 0 )                                    // remove element
    ->filter()                                       // remove empty values
    ->sort()                                         // sort elements
    ->col( 'value', 'id' )                           // create ['three' => 'value3']
    ->first();                                       // return first value

You can still use:

$map[] = ['id' => 'three', 'value' => 'value3'];
$value = $map[0];
count( $map );
foreach( $map as $key => value );

Use callbacks:

Also, the map object allows you to pass anonymous functions to a lot of methods, e.g.:

$map->each( function( $val, $key ) {
	echo $key . ': ' . $val;
} );

jQuery style:

If your map elements are objects, you can call their methods for each object and get the result as new map just like in jQuery:

// MyClass implements setId() (returning $this) and getCode() (initialized by constructor)

$map = Map::from( ['a' => new MyClass( 'x' ), 'b' => new MyClass( 'y' )] );
$map->setStatus( 1 )->getCode()->toArray();

This will call setStatus( 1 ) on both objects. If setStatus() implementation returns $this, the new map will also contain:

['a' => MyClass(), 'b' => MyClass()]

On those new map elements, getCode() will be called which returns x for the first object and y for the second. The map created from the results of getCode() will return:

['a' => 'x', 'b' => 'y']

Methods

• function is_map() : Tests if the variable is a map object
• function map() : Creates a new map from elements
• __construct() : Creates a new map
• __call() : Calls a custom method
• __callStatic() : Calls a custom method statically
• arsort() : Reverse sort elements with keys
• asort() : Sort elements with keys
• chunk() : Splits the map into chunks
• clear() : Removes all elements
• col() : Creates a key/value mapping
• collapse() : Collapses multi-dimensional elements
• combine() : Combines the keys with the values
• concat() : Combines the elements
• copy() : Creates a new copy
• count() : Returns the number of elements
• countBy() : Counts how often the same values are in the map
• diff() : Returns the missing elements
• diffAssoc() : Returns the missing elements and checks keys
• diffKeys() : Returns the missing elements by keys
• dump() : Dumps the map content
• each() : Applies a callback to each element
• empty() : Tests if map is empty
• equals() : Tests if map contents are equal
• except() : Returns a new map without the passed element keys
• filter() : Applies a filter to the map elements
• find() : Returns the first matching element
• first() : Returns the first element
• firstKey() : Returns the first key
• flip() : Exchanges keys with their values
• flat() : Flattens multi-dimensional elements
• from() : Creates a new map from passed elements
• get() : Returns an element by key
• getIterator() : Returns an iterator for the elements
• groupBy() : Groups associative array elements or objects
• has() : Tests if a key exists
• in() : Tests if element is included
• includes() : Tests if element is included
• intersect() : Returns the shared elements
• intersectAssoc() : Returns the shared elements and checks keys
• intersectKeys() : Returns the shared elements by keys
• is() : Tests if the map consists of the same keys and values
• isEmpty() : Tests if map is empty
• join() : Returns concatenated elements as string
• keys() : Returns the keys
• krsort() : Reverse sort elements by keys
• ksort() : Sort elements by keys
• last() : Returns the last element
• lastKey() : Returns the last key
• map() : Applies a callback to each element and returns the results
• merge() : Combines elements overwriting existing ones
• method() : Registers a custom method
• offsetExists() : Checks if the key exists
• offsetGet() : Returns an element by key
• offsetSet() : Overwrites an element
• offsetUnset() : Removes an element by key
• only() : Returns only those elements specified by the keys
• pipe() : Applies a callback to the map
• pop() : Returns and removes the last element
• pull() : Returns and removes an element by key
• push() : Adds an element to the end
• random() : Returns random elements
• reduce() : Computes a value for the map content
• remove() : Removes an element by key
• replace() : Replaces elements recursively
• reverse() : Reverses the array order
• rsort() : Reverse sort elements
• search() : Find the key of an element
• set() : Overwrites an element
• shift() : Returns and removes the first element
• shuffle() : Randomizes the element order
• slice() : Returns a slice of the map
• some() : Tests if at least one element is included
• sort() : Sorts elements
• split() : Splits a string into map elements
• splice() : Replaces a slice by new elements
• toArray() : Returns the plain array
• toJson() : Returns the elements in JSON format
• toUrl() : Creates a HTTP query string
• uasort() : Sorts elements with keys using callback
• uksort() : Sorts elements by keys using callback
• union() : Combines the element without overwriting
• unique() : Returns unique elements
• unshift() : Adds an element at the beginning
• usort() : Sorts elements using callback
• values() : Returns all elements with new keys
• walk() : Applies the given callback to all elements

Method documentation

is_map() function

Tests if the variable is a map object

function is_map( $var ) : bool

• @param mixed $var Variable to test

map() function

Returns a new map for the passed elements.

function map( $elements = [] ) : \Aimeos\Map

• @param mixed $elements List of elements or single value
• @return \Aimeos\Map Map instance

Examples:

Map::from( [] );
Map::from( null );
Map::from( 'a' );
Map::from( new Map() );
Map::from( new ArrayObject() );

Results:

A new map instance containing the list of elements. In case of an empty array or null, the map object will contain an empty list. If a map object is passed, it will be returned instead of creating a new instance.

__construct()

Creates a new map.

public function __construct( iterable $elements = [] )

• @param iterable $elements List of elements

__call()

Handles dynamic calls to custom methods for the class.

Calls a custom method added by Map::method(). The called method has access to the internal array by using $this->items.

public function __call( string $name, array $params )

• @param string $name Method name
• @param array $params List of parameters
• @return mixed|self Result from called function or map with results from the element methods

Examples:

Map::method( 'case', function( $case = CASE_LOWER ) {
    return new self( array_change_key_case( $this->items, $case ) );
} );
Map::from( ['a' => 'bar'] )->case( CASE_UPPER );

$item = new MyClass(); // with method setStatus() (returning $this) and getCode() implemented
Map::from( [$item, $item] )->setStatus( 1 )->getCode()->toArray();

Results:

The first example will return ['A' => 'bar'].

The second one will call the setStatus() method of each element in the map and use their return values to create a new map. On the new map, the getCode() method is called for every element and its return values are also stored in a new map. This last map is then returned. If the elements are not objects or don't implement the method, they are skipped. If this applies to all elements, an empty map is returned. The map keys from the original map are preserved in the returned map.

__callStatic()

Handles static calls to custom methods for the class.

Calls a custom method added by Map::method() statically. The called method has no access to the internal array because no object is available.

public static function __callStatic( string $name, array $params )

• @param string $name Method name
• @param array $params List of parameters
• @return mixed Result from called function
• @throws \BadMethodCallException

Examples:

Map::method( 'foo', function( $arg1, $arg2 ) {} );
Map::foo( $arg1, $arg2 );

arsort()

Sorts all elements in reverse order and maintains the key association.

public function arsort( int $options = SORT_REGULAR ) : self

• @param int $options Sort options for arsort()
• @return self Updated map for fluid interface

Examples:

Map::from( ['b' => 0, 'a' => 1] )->arsort();
Map::from( [1 => 'a', 0 => 'b'] )->arsort();

Results:

['a' => 1, 'b' => 0]
[0 => 'b', 1 => 'a']

The parameter modifies how the values are compared. Possible parameter values are:

• SORT_REGULAR : compare elements normally (don't change types)
• SORT_NUMERIC : compare elements numerically
• SORT_STRING : compare elements as strings
• SORT_LOCALE_STRING : compare elements as strings, based on the current locale or changed by setlocale()
• SORT_NATURAL : compare elements as strings using "natural ordering" like natsort()
• SORT_FLAG_CASE : use SORT_STRING|SORT_FLAG_CASE and SORT_NATURAL|SORT_FLAG_CASE to sort strings case-insensitively

The keys are preserved using this method and no new map is created.

asort()

Sorts all elements and maintains the key association.

public function asort( int $options = SORT_REGULAR ) : self

• @param int $options Sort options for asort()
• @return self Updated map for fluid interface

Examples:

Map::from( ['a' => 1, 'b' => 0] )->asort();
Map::from( [0 => 'b', 1 => 'a'] )->asort();

Results:

['b' => 0, 'a' => 1]
[1 => 'a', 0 => 'b']

The parameter modifies how the values are compared. Possible parameter values are:

• SORT_REGULAR : compare elements normally (don't change types)
• SORT_NUMERIC : compare elements numerically
• SORT_STRING : compare elements as strings
• SORT_LOCALE_STRING : compare elements as strings, based on the current locale or changed by setlocale()
• SORT_NATURAL : compare elements as strings using "natural ordering" like natsort()
• SORT_FLAG_CASE : use SORT_STRING|SORT_FLAG_CASE and SORT_NATURAL|SORT_FLAG_CASE to sort strings case-insensitively

The keys are preserved using this method and no new map is created.

chunk()

Chunks the map into arrays with the given number of elements.

public function chunk( int $size, bool $preserve = false ) : self

• @param int $size Maximum size of the sub-arrays
• @param bool $preserve Preserve keys in new map
• @return self New map with elements chunked in sub-arrays
• @throws \InvalidArgumentException If size is smaller than 1

Examples:

Map::from( [0, 1, 2, 3, 4] )->chunk( 3 );
Map::from( ['a' => 0, 'b' => 1, 'c' => 2] )->chunk( 2 );

Results:

[[0, 1, 2], [3, 4]]
[['a' => 0, 'b' => 1], ['c' => 2]]

The last chunk may contain less elements than the given number.

The sub-arrays of the returned map are plain PHP arrays. If you need Map objects, then wrap them with Map::from() when you iterate over the map.

clear()

Removes all elements from the current map.

public function clear() : self

• @return self Same map for fluid interface

col()

Returns the values of a single column/property from an array of arrays or list of elements in a new map.

public function col( string $valuecol = null, string $indexcol = null ) : self

• @param string|null $valuecol Name of the value property
• @param string|null $indexcol Name of the index property
• @return self New instance with mapped entries

Examples:

Map::from( [['id' => 'i1', 'val' => 'v1'], ['id' => 'i2', 'val' => 'v2']] )->col( 'val' );
Map::from( [['id' => 'i1', 'val' => 'v1'], ['id' => 'i2', 'val' => 'v2']] )->col( 'val', 'id' );
Map::from( [['id' => 'i1', 'val' => 'v1'], ['id' => 'i2', 'val' => 'v2']] )->col( null, 'id' );

Results:

['v1', 'v2']
['i1' => 'v1', 'i2' => 'v2']
['i1' => ['id' => 'i1', 'val' => 'v1'], 'i2' => ['id' => 'i2', 'val' => 'v2']]

If $indexcol is omitted, the result will be indexed from 0-n. The col() method works for objects implementing the __isset() and __get() methods too.

collapse()

Collapses all sub-array elements recursively to a new map.

public function collapse( int $depth = null ) : self

• @param int|null $depth Number of levels to collapse for multi-dimensional arrays or NULL for all
• @return self New map with all sub-array elements added into it recursively, up to the specified depth

Examples:

Map::from( [0 => ['a' => 0, 'b' => 1], 1 => ['c' => 2, 'd' => 3]] )->collapse();
Map::from( [0 => ['a' => 0, 'b' => 1], 1 => ['a' => 2]] )->collapse();
Map::from( [0 => [0 => 0, 1 => 1], 1 => [0 => ['a' => 2, 0 => 3], 1 => 4]] )->collapse();
Map::from( [0 => [0 => 0, 'a' => 1], 1 => [0 => ['b' => 2, 0 => 3], 1 => 4]] )->collapse( 1 );
Map::from( [0 => [0 => 0, 'a' => 1], 1 => Map::from( [0 => ['b' => 2, 0 => 3], 1 => 4] )] )->collapse();

Results:

['a' => 0, 'b' => 1, 'c' => 2, 'd' => 3]
['a' => 2, 'b' => 1]
[0 => 3, 1 => 4, 'a' => 2]
[0 => ['b' => 2, 0 => 3], 1 => 4, 'a' => 1]
[0 => 3, 'a' => 1, 'b' => 2, 1 => 4]

The keys are preserved and already existing elements will be overwritten. This is also true for numeric keys!

A value smaller than 1 for depth will return the same map elements. Collapsing does also work if elements implement the "Traversable" interface (which the Map object does).

This method is similar than flat() but replaces already existing elements.

concat()

Pushs all of the given elements onto the map without creating a new map.

public function concat( iterable $elements ) : self

• @param iterable $elements List of elements
• @return self Updated map for fluid interface

Examples:

Map::from( ['foo'] )->concat( new Map( ['bar'] ));

Results:

['foo', 'bar']

combine()

Combines the values of the map as keys with the passed elements as values.

public function combine( iterable $values ) : self

• @param iterable $values Values of the new map
• @return self New map

Examples:

Map::from( ['name', 'age'] )->combine( ['Tom', 29] );

Results:

['name' => 'Tom', 'age' => 29]

copy()

Creates a new map with the same elements.

Both maps share the same array until one of the map objects modifies the array. Then, the array is copied and the copy is modfied (copy on write).

public function copy() : self

• @return self New map

count()

Counts the number of elements in the map.

public function count() : int

• @return int Number of elements

countBy()

Counts how often the same values are in the map.

public function countBy( callable $callback = null ) : self

• @param callable|null $callback Function with (value, key) parameters which returns the value to use for counting
• @return self New map with values as keys and their count as value

Examples:

Map::from( [1, 'foo', 2, 'foo', 1] )->countBy();
Map::from( [1.11, 3.33, 3.33, 9.99] )->countBy();
Map::from( ['a@gmail.com', 'b@yahoo.com', 'c@gmail.com'] )->countBy( function( $email ) {
    return substr( strrchr( $email, '@' ), 1 );
} );

Results:

[1 => 2, 'foo' => 2, 2 => 1]
['1.11' => 1, '3.33' => 2, '9.99' => 1]
['gmail.com' => 2, 'yahoo.com' => 1]

diff()

Returns the keys/values in the map whose values are not present in the passed elements in a new map.

public function diff( iterable $elements, callable $callback = null ) : self

• @param iterable $elements List of elements
• @param callable|null $callback Function with (valueA, valueB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self New map

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->diff( ['bar'] );

Results:

['a' => 'foo']

If a callback is passed, the given function will be used to compare the values. The function must accept two parameters (value A and B) and must return -1 if value A is smaller than value B, 0 if both are equal and 1 if value A is greater than value B. Both, a method name and an anonymous function can be passed:

Map::from( [0 => 'a'] )->diff( [0 => 'A'], 'strcasecmp' );
Map::from( ['b' => 'a'] )->diff( ['B' => 'A'], 'strcasecmp' );
Map::from( ['b' => 'a'] )->diff( ['c' => 'A'], function( $valA, $valB ) {
    return strtolower( $valA ) <=> strtolower( $valB );
} );

All examples will return an empty map because both contain the same values when compared case insensitive.

diffAssoc()

Returns the keys/values in the map whose keys and values are not present in the passed elements in a new map.

public function diffAssoc( iterable $elements, callable $callback = null ) : self

• @param iterable $elements List of elements
• @param callable|null $callback Function with (valueA, valueB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self New map

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->diffAssoc( new Map( ['foo', 'b' => 'bar'] ) );

Results:

['a' => 'foo']

If a callback is passed, the given function will be used to compare the values. The function must accept two parameters (value A and B) and must return -1 if value A is smaller than value B, 0 if both are equal and 1 if value A is greater than value B. Both, a method name and an anonymous function can be passed:

Map::from( [0 => 'a'] )->diffAssoc( [0 => 'A'], 'strcasecmp' );
Map::from( ['b' => 'a'] )->diffAssoc( ['B' => 'A'], 'strcasecmp' );
Map::from( ['b' => 'a'] )->diffAssoc( ['c' => 'A'], function( $valA, $valB ) {
    return strtolower( $valA ) <=> strtolower( $valB );
} );

The first example will return an empty map because both contain the same values when compared case insensitive. The second and third example will return an empty map because 'A' is part of the passed array but the keys doesn't match ("b" vs. "B" and "b" vs. "c").

diffKeys()

Returns the key/value pairs from the map whose keys are not present in the passed elements in a new map.

public function diffKeys( iterable $elements, callable $callback = null ) : self

• @param iterable $elements List of elements
• @param callable|null $callback Function with (keyA, keyB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self New map

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->diffKeys( new Map( ['foo', 'b' => 'baz'] ) );

Results:

['a' => 'foo']

If a callback is passed, the given function will be used to compare the keys. The function must accept two parameters (key A and B) and must return -1 if key A is smaller than key B, 0 if both are equal and 1 if key A is greater than key B. Both, a method name and an anonymous function can be passed:

Map::from( [0 => 'a'] )->diffKeys( [0 => 'A'], 'strcasecmp' );
Map::from( ['b' => 'a'] )->diffKeys( ['B' => 'X'], 'strcasecmp' );
Map::from( ['b' => 'a'] )->diffKeys( ['c' => 'a'], function( $keyA, $keyB ) {
    return strtolower( $keyA ) <=> strtolower( $keyB );
} );

The first and second example will return an empty map because both contain the same keys when compared case insensitive. The third example will return ['b' => 'a'] because the keys doesn't match ("b" vs. "c").

dump()

Dumps the map content using the given function (print_r by default).

The dump() method is very helpful to see what are the map elements passed between two map methods in a method call chain.

public function dump( callable $callback = null ) : self

• @param callable $callback Function receiving the map elements as parameter (optional)
• @return self Same map for fluid interface

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->dump()->sort()->dump( 'var_dump' );

Results:

Array
(
    [a] => foo
    [b] => bar
)
array(1) {
  ["b"]=>
  string(3) "bar"
  ["a"]=>
  string(3) "foo"
}

each()

Executes a callback over each entry until FALSE is returned.

public function each( \Closure $callback ) : self

• @param \Closure $callback Function with (value, key) parameters and returns TRUE/FALSE
• @return self Same map for fluid interface

Examples:

$result = [];
Map::from( [0 => 'a', 1 => 'b'] )->each( function( $value, $key ) use ( &$result ) {
    $result[$key] = strtoupper( $value );
    return false;
} );

The $result array will contain [0 => 'A'] because FALSE is returned after the first entry and all other entries are then skipped.

empty()

Determines if the map is empty or not.

public function empty() : bool

• @return bool TRUE if map is empty, FALSE if not

Examples:

Map::from( [] )->empty();
Map::from( ['a'] )->empty();

Results:

The first example returns TRUE while the second returns FALSE

The method is equivalent to isEmpty().

equals()

Tests if the passed elements are equal to the elements in the map.

public function equals( iterable $elements, $assoc = false ) : bool

• @param iterable $elements List of elements to test against
• @param bool $assoc TRUE to compare keys too, FALSE to compare only values
• @return bool TRUE if both are equal, FALSE if not

Examples:

Map::from( ['a'] )->equals( ['a', 'b'] );
Map::from( ['a', 'b'] )->equals( ['b'] );
Map::from( ['a', 'b'] )->equals( ['b', 'a'] );

Results:

The first and second example will return FALSE, the third example will return TRUE

The method differs to is() in the fact that it doesn't care about the keys by default. The elements are only loosely compared and the keys are ignored.

If the second parameter is TRUE, keys are compared too:

Map::from( [0 => 'a'] )->equals( [1 => 'a'], true );
Map::from( [1 => 'a'] )->equals( [0 => 'a'], true );
Map::from( [0 => 'a'] )->equals( [0 => 'a'], true );

The first and second example above will also return FALSE and only the third example will return TRUE

Keys and values are compared by their string values:

(string) $item1 === (string) $item2

except()

Returns a new map without the passed element keys.

public function except( $keys ) : self

• @param mixed|array $keys List of keys to remove
• @return self New map

Examples:

Map::from( ['a' => 1, 'b' => 2, 'c' => 3] )->except( 'b' );
Map::from( [1 => 'a', 2 => 'b', 3 => 'c'] )->except( [1, 3] );

Results:

['a' => 1, 'c' => 3]
[2 => 'b']

filter()

Runs a filter over each element of the map and returns a new map.

public function filter( callable $callback = null ) : self

• @param callable|null $callback Function with (item) parameter and returns TRUE/FALSE
• @return self New map

Examples:

Map::from( [2 => 'a', 6 => 'b', 13 => 'm', 30 => 'z'] )->filter( function( $value, $key ) {
    return `$key` < 10 && `$value` < 'n';
} );

Results:

['a', 'b']

If no callback is passed, all values which are empty, null or false will be removed if their value converted to boolean is FALSE:

(bool) $value === false

find()

Returns the first matching element where the callback returns TRUE.

public function find( \Closure $callback, bool $reverse = false )

• @param \Closure $callback Function with (value, key) parameters and returns TRUE/FALSE
• @param bool $reverse TRUE to test elements from back to front, FALSE for front to back (default)
• @return mixed|null First matching value or NULL

Examples:

Map::from( ['a', 'c', 'e'] )->find( function( $value, $key ) {
    return $value >= 'b';
} );
Map::from( ['a', 'c', 'e'] )->find( function( $value, $key ) {
    return $value >= 'b';
}, true );

Results:

The first example will return 'c' while the second will return 'e' (last element).

first()

Returns the first element from the map.

public function first( $default = null )

• @param mixed $default Default value or exception if the map contains no elements
• @return mixed First value of map, (generated) default value or an exception

Examples:

Map::from( ['a', 'b'] )->first();
Map::from( [] )->first( 'x' );
Map::from( [] )->first( new \Exception( 'error' ) );
Map::from( [] )->first( function() { return rand(); } );

Results:

The first example will return 'a' and the second one 'x'. The third example will throw the exception passed if the map contains no elements. In the fourth example, a random value generated by the closure function will be returned.

firstKey()

Returns the first key from the map.

public function firstKey()

• @return mixed First key of map or NULL if empty

Examples:

Map::from( ['a' => 1, 'b' => 2] )->lastKey();
Map::from( [] )->lastKey();

Results:

The first example will return 'a' and the second one NULL.

flat()

Creates a new map with all sub-array elements added recursively

public function flat( int $depth = null ) : self

• @param int|null $depth Number of levels to flatten multi-dimensional arrays
• @return self New map with all sub-array elements added into it recursively, up to the specified depth

Examples:

Map::from( [[0, 1], [2, 3]] )->flat();
Map::from( [[0, 1], [[2, 3], 4]] )->flat();
Map::from( [[0, 1], [[2, 3], 4]] )->flat( 1 );
Map::from( [[0, 1], Map::from( [[2, 3], 4] )] )->flat();

Results:

[0, 1, 2, 3]
[0, 1, 2, 3, 4]
[0, 1, [2, 3], 4]
[0, 1, 2, 3, 4]

The keys are not preserved and the new map elements will be numbered from 0-n. A value smaller than 1 for depth will return the same map elements indexed from 0-n. Flattening does also work if elements implement the "Traversable" interface (which the Map object does).

This method is similar than collapse() but doesn't replace existing elements.

flip()

Exchanges the keys with their values and vice versa.

public function flip() : self

• @return self New map with keys as values and values as keys

Examples:

Map::from( ['a' => 'X', 'b' => 'Y'] )->flip();

Results:

['X' => 'a', 'Y' => 'b']

from()

Creates a new map instance if the value isn't one already.

public static function from( $elements = [] ) : self

• @param mixed $elements List of elements or single value
• @return self New map

Examples:

Map::from( [] );
Map::from( null );
Map::from( 'a' );
Map::from( new Map() );
Map::from( new ArrayObject() );

Results:

A new map instance containing the list of elements. In case of an empty array or null, the map object will contain an empty list. If a map object is passed, it will be returned instead of creating a new instance.

get()

Returns an element from the map by key.

public function get( $key, $default = null )

• @param mixed $key Key of the requested item
• @param mixed $default Default value if no element matches
• @return mixed Value from map or default value

Examples:

Map::from( ['a' => 'X', 'b' => 'Y'] )->get( 'a' );
Map::from( ['a' => 'X', 'b' => 'Y'] )->get( 'c', 'Z' );
Map::from( [] )->get( new \Exception( 'error' ) );
Map::from( [] )->get( function() { return rand(); } );

Results:

The first example will return "X", the second "Z". The third example will throw the exception passed if the map contains no elements. In the fourth example, a random value generated by the closure function will be returned.

getIterator()

Returns an iterator for the elements.

This method will be used by e.g. foreach() to loop over all entries:

public function getIterator() : \Iterator

• @return \Iterator Over map elements

Examples:

foreach( Map::from( ['a', 'b'] ) as $value )

groupBy()

Groups associative array elements or objects by the passed key or closure.

Instead of overwriting items with the same keys like to the col() method does, groupBy() keeps all entries in sub-arrays. It's preserves the keys of the orignal map entries too.

public function groupBy( $key ) : self

• @param \Closure|string $key Closure function with (item, idx) parameters returning the key or the key itself to group by
• @return self New map with elements grouped by the given key

Examples:

$list = [
    10 => ['aid' => 123, 'code' => 'x-abc'],
    20 => ['aid' => 123, 'code' => 'x-def'],
    30 => ['aid' => 456, 'code' => 'x-def']
];
Map::from( $list )->groupBy( 'aid' );
Map::from( $list )->groupBy( function( $item, $key ) {
    return substr( $item['code'], -3 );
} );
Map::from( $list )->groupBy( 'xid' );

Results:

[ 123 => [ 10 => ['aid' => 123, 'code' => 'x-abc'], 20 => ['aid' => 123, 'code' => 'x-def'] ], 456 => [ 30 => ['aid' => 456, 'code' => 'x-def'] ] ] [ 'abc' => [ 10 => ['aid' => 123, 'code' => 'x-abc'] ], 'def' => [ 20 => ['aid' => 123, 'code' => 'x-def'], 30 => ['aid' => 456, 'code' => 'x-def'] ] ] [ 'xid' => [ 10 => ['aid' => 123, 'code' => 'x-abc'], 20 => ['aid' => 123, 'code' => 'x-def'] 30 => ['aid' => 456, 'code' => 'x-def'] ] ]

In case the passed key doesn't exist in one or more items, these items are stored in a sub-array using passed string as key.

has()

Determines if a key or several keys exists in the map.

If several keys are passed as array, all keys must exist in the map for TRUE to be returned.

public function has( $key ) : bool

• @param mixed|array $key Key of the requested item
• @return bool TRUE if key is available in map, FALSE if not

Examples:

Map::from( ['a' => 'X', 'b' => 'Y'] )->has( 'a' );
Map::from( ['a' => 'X', 'b' => 'Y'] )->has( ['a', 'b'] );
Map::from( ['a' => 'X', 'b' => 'Y'] )->has( 'c' );
Map::from( ['a' => 'X', 'b' => 'Y'] )->has( ['a', 'c'] );
Map::from( ['a' => 'X', 'b' => 'Y'] )->has( 'X' );

Results:

The first and second example will return TRUE while the other ones will return FALSE

in()

Tests if the passed element or elements are part of the map.

public function in( $element, bool $strict = false ) : bool

• @param mixed|array $element Element or elements to search for in the map
• @param bool $strict TRUE to check the type too, using FALSE '1' and 1 will be the same
• @return bool TRUE if all elements are available in map, FALSE if not

Examples:

Map::from( ['a', 'b'] )->in( 'a' );
Map::from( ['a', 'b'] )->in( ['a', 'b'] );
Map::from( ['a', 'b'] )->in( 'x' );
Map::from( ['a', 'b'] )->in( ['a', 'x'] );
Map::from( ['1', '2'] )->in( 2, true );

Results:

The first and second example will return TRUE while the other ones will return FALSE

includes()

Tests if the passed element or elements are part of the map.

public function includes( $element, bool $strict = false ) : bool

• @param mixed|array $element Element or elements to search for in the map
• @param bool $strict TRUE to check the type too, using FALSE '1' and 1 will be the same
• @return bool TRUE if all elements are available in map, FALSE if not

Examples:

Map::from( ['a', 'b'] )->includes( 'a' );
Map::from( ['a', 'b'] )->includes( ['a', 'b'] );
Map::from( ['a', 'b'] )->includes( 'x' );
Map::from( ['a', 'b'] )->includes( ['a', 'x'] );
Map::from( ['1', '2'] )->includes( 2, true );

Results:

The first and second example will return TRUE while the other ones will return FALSE

This method is an alias for in(). For performance reasons, in() should be preferred because it uses one method call less than includes().

intersect()

Returns all values in a new map that are available in both, the map and the given elements.

public function intersect( iterable $elements, callable $callback = null ) : self

• @param iterable $elements List of elements
• @param callable|null $callback Function with (valueA, valueB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self New map

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->intersect( ['bar'] );

Results:

['b' => 'bar']

If a callback is passed, the given function will be used to compare the values. The function must accept two parameters (value A and B) and must return -1 if value A is smaller than value B, 0 if both are equal and 1 if value A is greater than value B. Both, a method name and an anonymous function can be passed:

Map::from( [0 => 'a'] )->intersect( [0 => 'A'], 'strcasecmp' );
Map::from( ['b' => 'a'] )->intersect( ['B' => 'A'], 'strcasecmp' );
Map::from( ['b' => 'a'] )->intersect( ['c' => 'A'], function( $valA, $valB ) {
    return strtolower( $valA ) <=> strtolower( $valB );
} );

All examples will return a map containing ['a'] because both contain the same values when compared case insensitive.

intersectAssoc()

Returns all values in a new map that are available in both, the map and the given elements while comparing the keys too.

public function intersectAssoc( iterable $elements, callable $callback = null ) : self

• @param iterable $elements List of elements
• @param callable|null $callback Function with (valueA, valueB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self New map

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->intersectAssoc( new Map( ['foo', 'b' => 'bar'] ) );

Results:

['a' => 'foo']

If a callback is passed, the given function will be used to compare the values. The function must accept two parameters (value A and B) and must return -1 if value A is smaller than value B, 0 if both are equal and 1 if value A is greater than value B. Both, a method name and an anonymous function can be passed:

Map::from( [0 => 'a'] )->intersectAssoc( [0 => 'A'], 'strcasecmp' );
Map::from( ['b' => 'a'] )->intersectAssoc( ['B' => 'A'], 'strcasecmp' );
Map::from( ['b' => 'a'] )->intersectAssoc( ['c' => 'A'], function( $valA, $valB ) {
    return strtolower( $valA ) <=> strtolower( $valB );
} );

The first example will return [0 => 'a'] because both contain the same values when compared case insensitive. The second and third example will return an empty map because the keys doesn't match ("b" vs. "B" and "b" vs. "c").

intersectKeys()

Returns all values in a new map that are available in both, the map and the given elements by comparing the keys only.

public function intersectKeys( iterable $elements, callable $callback = null ) : self

• @param iterable $elements List of elements
• @param callable|null $callback Function with (keyA, keyB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self New map

Examples:

Map::from( ['a' => 'foo', 'b' => 'bar'] )->intersectKeys( new Map( ['foo', 'b' => 'baz'] ) );

Results:

['b' => 'bar']

If a callback is passed, the given function will be used to compare the keys. The function must accept two parameters (key A and B) and must return -1 if key A is smaller than key B, 0 if both are equal and 1 if key A is greater than key B. Both, a method name and an anonymous function can be passed:

Map::from( [0 => 'a'] )->intersectKeys( [0 => 'A'], 'strcasecmp' );
Map::from( ['b' => 'a'] )->intersectKeys( ['B' => 'X'], 'strcasecmp' );
Map::from( ['b' => 'a'] )->intersectKeys( ['c' => 'a'], function( $keyA, $keyB ) {
    return strtolower( $keyA ) <=> strtolower( $keyB );
} );

The first example will return a map with [0 => 'a'] and the second one will return a map with ['b' => 'a'] because both contain the same keys when compared case insensitive. The third example will return an empty map because the keys doesn't match ("b" vs. "c").

is()

Tests if the map consists of the same keys and values

public function is( iterable $list, bool $strict = false ) : bool

• @param iterable $list List of key/value pairs to compare with
• @param bool $strict TRUE for comparing order of elements too, FALSE for key/values only
• @param bool TRUE if given list is equal, FALSE if not

Examples:

Map::from( ['a', 'b'] )->is( ['b', 'a'] );
Map::from( ['a', 'b'] )->is( ['b', 'a'], true );
Map::from( [1, 2] )->is( ['1', '2'] );

Results: The first example returns TRUE while the second and third one returns FALSE

isEmpty()

Determines if the map is empty or not.

public function isEmpty() : bool

• @return bool TRUE if map is empty, FALSE if not

Examples:

Map::from( [] )->isEmpty();
Map::from( ['a'] )-isEmpty();

Results:

The first example returns TRUE while the second returns FALSE

The method is equivalent to empty().

join()

Concatenates the string representation of all elements.

Objects that implement __toString() does also work, otherwise (and in case of arrays) a PHP notice is generated. NULL and FALSE values are treated as empty strings.

public function join( $glue = '' ) : string

• @param string $glue Character or string added between elements
• @return string String of concatenated map elements

Examples:

Map::from( ['a', 'b', false] )->join();
Map::from( ['a', 'b', null, false] )->join( '-' );

Results:

The first example will return "ab" while the second one will return "a-b--"

keys()

Returns the keys of the map elements in a new map object.

public function keys() : self

• @return self New map

Examples:

Map::from( ['a', 'b'] );
Map::from( ['a' => 0, 'b' => 1] );

Results:

The first example returns a map containing [0, 1] while the second one will return a map with ['a', 'b'].

krsort()

Sorts the elements by their keys in reverse order.

public function krsort( int $options = SORT_REGULAR ) : self

• @param int $options Sort options for krsort()
• @return self Updated map for fluid interface

Examples:

Map::from( ['b' => 0, 'a' => 1] )->krsort();
Map::from( [1 => 'a', 0 => 'b'] )->krsort();

Results:

['a' => 1, 'b' => 0]
[0 => 'b', 1 => 'a']

The parameter modifies how the keys are compared. Possible values are:

• SORT_REGULAR : compare elements normally (don't change types)
• SORT_NUMERIC : compare elements numerically
• SORT_STRING : compare elements as strings
• SORT_LOCALE_STRING : compare elements as strings, based on the current locale or changed by setlocale()
• SORT_NATURAL : compare elements as strings using "natural ordering" like natsort()
• SORT_FLAG_CASE : use SORT_STRING|SORT_FLAG_CASE and SORT_NATURAL|SORT_FLAG_CASE to sort strings case-insensitively

The keys are preserved using this method and no new map is created.

ksort()

Sorts the elements by their keys.

public function ksort( int $options = SORT_REGULAR ) : self

• @param int $options Sort options for ksort()
• @return self Updated map for fluid interface

Examples:

Map::from( ['b' => 0, 'a' => 1] )->ksort();
Map::from( [1 => 'a', 0 => 'b'] )->ksort();

Results:

['a' => 1, 'b' => 0]
[0 => 'b', 1 => 'a']

The parameter modifies how the keys are compared. Possible values are:

• SORT_REGULAR : compare elements normally (don't change types)
• SORT_NUMERIC : compare elements numerically
• SORT_STRING : compare elements as strings
• SORT_LOCALE_STRING : compare elements as strings, based on the current locale or changed by setlocale()
• SORT_NATURAL : compare elements as strings using "natural ordering" like natsort()
• SORT_FLAG_CASE : use SORT_STRING|SORT_FLAG_CASE and SORT_NATURAL|SORT_FLAG_CASE to sort strings case-insensitively

The keys are preserved using this method and no new map is created.

last()

Returns the last element from the map.

public function last( $default = null )

• @param mixed $default Default value or exception if the map contains no elements
• @return mixed Last value of map, (generated) default value or an exception

Examples:

Map::from( ['a', 'b'] )->last();
Map::from( [] )->last( 'x' );
Map::from( [] )->last( new \Exception( 'error' ) );
Map::from( [] )->last( function() { return rand(); } );

Results:

The first example will return 'b' and the second one 'x'. The third example will throw the exception passed if the map contains no elements. In the fourth example, a random value generated by the closure function will be returned.

lastKey()

Returns the last key from the map.

public function lastKey()

• @return mixed Last key of map or NULL if empty

Examples:

Map::from( ['a' => 1, 'b' => 2] )->lastKey();
Map::from( [] )->lastKey();

Results:

The first example will return 'b' and the second one NULL.

map()

Calls the passed function once for each element and returns a new map for the result.

public function map( callable $callback ) : self

• @param callable $callback Function with (value, key) parameters and returns computed result
• @return self New map with the original keys and the computed values

Examples:

Map::from( ['a' => 2, 'b' => 4] )->map( function( $value, $key ) {
    return $value * 2;
} );

Results:

['a' => 4, 'b' => 8]

merge()

Merges the map with the given elements without returning a new map.

Elements with the same non-numeric keys will be overwritten, elements with the same numeric keys will be added.

public function merge( iterable $elements, bool $recursive = false ) : self

• @param iterable $elements List of elements
• @param bool $recursive TRUE to merge nested arrays too, FALSE for first level elements only
• @return self Updated map for fluid interface

Examples:

Map::from( ['a', 'b'] )->merge( ['b', 'c'] );
Map::from( ['a' => 1, 'b' => 2] )->merge( ['b' => 4, 'c' => 6] );
Map::from( ['a' => 1, 'b' => 2] )->merge( ['b' => 4, 'c' => 6], true );

Results:

['a', 'b', 'b', 'c']
['a' => 1, 'b' => 4, 'c' => 6]
['a' => 1, 'b' => [2, 4], 'c' => 6]

The method is similar to replace() but doesn't replace elements with the same numeric keys. If you want to be sure that all passed elements are added without replacing existing ones, use concat() instead.

method()

Registers a custom method that has access to the class properties if called non-static.

public static function method( string $name, \Closure $function )

• @param string $name Method name
• @param \Closure $function Anonymous method

Examples:

Map::method( 'foo', function( $arg1, $arg2 ) {
    return $this->elements;
} );

Dynamic calls have access to the class properties:

(new Map( ['bar'] ))->foo( $arg1, $arg2 );

Static calls yield an error because $this->elements isn't available:

Map::foo( $arg1, $arg2 );

offsetExists()

Determines if an element exists at an offset.

public function offsetExists( $key )

• @param mixed $key Key to check for
• @return bool TRUE if key exists, FALSE if not

Examples:

$map = Map::from( ['a' => 1, 'b' => 3] );
isset( $map['b'] );
isset( $map['c'] );

Results:

The first isset() will return TRUE while the second one will return FALSE

offsetGet()

Returns an element at a given offset.

public function offsetGet( $key )

• @param mixed $key Key to return the element for
• @return mixed Value associated to the given key

Examples:

$map = Map::from( ['a' => 1, 'b' => 3] );
$map['b'];

Results:

$map['b'] will return 3

offsetSet()

Sets the element at a given offset.

public function offsetSet( $key, $value )

• @param mixed $key Key to set the element for
• @param mixed $value New value set for the key

Examples:

$map = Map::from( ['a' => 1] );
$map['b'] = 2;
$map[0] = 4;

Results:

['a' => 1, 'b' => 2, 0 => 4]

offsetUnset()

Unsets the element at a given offset.

public function offsetUnset( $key )

• @param string $key Key for unsetting the item

Examples:

$map = Map::from( ['a' => 1] );
unset( $map['a'] );

Results:

The map will be empty

only()

Returns a new map with only those elements specified by the given keys.

public function only( $keys ) : self

• @param array|string|int $keys Keys of the elements that should be returned
• @return self New map with only the elements specified by the keys

Examples:

Map::from( ['a' => 1, 0 => 'b'] )->only( 'a' );
Map::from( ['a' => 1, 0 => 'b', 1 => 'c'] )->only( [0, 1] );

Results:

['a' => 1]
[0 => 'b', 1 => 'c']

pipe()

Passes the map to the given callback and return the result.

public function pipe( \Closure $callback )

• @param \Closure $callback Function with map as parameter which returns arbitrary result
• @return mixed Result returned by the callback

Examples:

Map::from( ['a', 'b'] )->pipe( function( $map ) {
    return strrev( $map->join( '-' ) );
} );

Results:

"b-a" will be returned

pop()

Returns and removes the last element from the map.

public function pop()

• @return mixed Last element of the map or null if empty

Examples:

Map::from( ['a', 'b'] )->pop();

Results:

"b" will be returned and the map only contains ['a'] afterwards

pull()

Returns and removes an element from the map by its key.

public function pull( $key, $default = null )

• @param mixed $key Key to retrieve the value for
• @param mixed $default Default value if key isn't available
• @return mixed Value from map or default value

Examples:

Map::from( ['a', 'b', 'c'] )->pull( 1 );
Map::from( ['a', 'b', 'c'] )->pull( 'x', 'none' );

Results:

The first example will return "b" and the map contains ['a', 'c'] afterwards. The second one will return "none" and the map content stays untouched.

push()

Adds an element onto the end of the map without returning a new map.

public function push( $value ) : self

• @param mixed $value Value to add to the end
• @return self Same map for fluid interface

Examples:

Map::from( ['a', 'b'] )->push( 'aa' );

Results:

['a', 'b', 'aa']

random()

Returns one or more random element from the map.

public function random( int $max = 1 ) : self

• @param int $max Maximum number of elements that should be returned
• @return self New map with key/element pairs from original map in random order
• @throws \InvalidArgumentException If requested number of elements is less than 1

Examples:

*  Map::from( [2, 4, 8, 16] )->random();
*  Map::from( [2, 4, 8, 16] )->random( 2 );
*  Map::from( [2, 4, 8, 16] )->random( 5 );

Results:

The first example will return a map including [0 => 8] or any other value, the second one will return a map with [0 => 16, 1 => 2] or any other values and the third example will return a map of the whole list in random order. The less elements are in the map, the less random the order will be, especially if the maximum number of values is high or close to the number of elements.

The keys of the original map are preserved in the returned map.

reduce()

Iteratively reduces the array to a single value using a callback function. Afterwards, the map will be empty.

public function reduce( callable $callback, $initial = null )

• @param callable $callback Function with (result, value) parameters and returns result
• @param mixed $initial Initial value when computing the result
• @return mixed Value computed by the callback function

Examples:

Map::from( [2, 8] )->reduce( function( $result, $value ) {
    return $result += $value;
}, 10 );

Results:

"20" will be returned because the sum is computed by 10 (initial value) + 2 + 8

remove()

Removes one or more elements from the map by its keys without returning a new map.

public function remove( $keys ) : self

• @param string|int|iterable $keys List of keys
• @return self Same map for fluid interface

Examples:

Map::from( ['a' => 1, 2 => 'b'] )->remove( 'a' );
Map::from( ['a' => 1, 2 => 'b'] )->remove( [2, 'a'] );

Results:

The first example will result in [2 => 'b'] while the second one resulting in an empty list

replace()

Replaces elements in the map with the given elements without returning a new map.

public function replace( iterable $elements, bool $recursive = true ) : self

• @param iterable $elements List of elements
• @param bool $recursive TRUE to replace recursively (default), FALSE to replace elements only
• @return self Updated map for fluid interface

Examples:

Map::from( ['a' => 1, 2 => 'b'] )->replace( ['a' => 2] );
Map::from( ['a' => 1, 'b' => ['c' => 3, 'd' => 4]] )->replace( ['b' => ['c' => 9]] );

Results:

['a' => 2, 2 => 'b']
['a' => 1, 'b' => ['c' => 9, 'd' => 4]]

The method is similar to merge() but also replaces elements with numeric keys. These would be added by merge() with a new numeric key.

reverse()

Reverses the element order without returning a new map.

public function reverse() : self

• @return self Updated map for fluid interface

Examples:

Map::from( ['a', 'b'] )->reverse();

Results:

['b', 'a']

rsort()

Sorts all elements in reverse order without maintaining the key association.

public function rsort( int $options = SORT_REGULAR ) : self

• @param int $options Sort options for rsort()
• @return self Updated map for fluid interface

Examples:

Map::from( ['a' => 1, 'b' => 0] )->rsort();
Map::from( [0 => 'b', 1 => 'a'] )->rsort();

Results:

[0 => 1, 1 => 0]
[0 => 'b', 1 => 'a']

The parameter modifies how the values are compared. Possible parameter values are:

• SORT_REGULAR : compare elements normally (don't change types)
• SORT_NUMERIC : compare elements numerically
• SORT_STRING : compare elements as strings
• SORT_LOCALE_STRING : compare elements as strings, based on the current locale or changed by setlocale()
• SORT_NATURAL : compare elements as strings using "natural ordering" like natsort()
• SORT_FLAG_CASE : use SORT_STRING|SORT_FLAG_CASE and SORT_NATURAL|SORT_FLAG_CASE to sort strings case-insensitively

The keys aren't preserved and elements get a new index. No new map is created

search()

Searches the map for a given value and return the corresponding key if successful.

public function search( $value, $strict = true )

• @param mixed $value Item to search for
• @param bool $strict TRUE if type of the element should be checked too
• @return mixed|null Value from map or null if not found

Examples:

Map::from( ['a', 'b', 'c'] )->search( 'b' );
Map::from( [1, 2, 3] )->search( '2', true );

Results:

The first example will return 1 (array index) while the second one will return NULL because the types doesn't match (int vs. string)

set()

Sets an element in the map by key without returning a new map.

public function set( $key, $value ) : self

• @param mixed $key Key to set the new value for
• @param mixed $value New element that should be set
• @return self Same map for fluid interface

Examples:

Map::from( ['a'] )->set( 1, 'b' );
Map::from( ['a'] )->set( 0, 'b' );

Results:

The first example results in ['a', 'b'] while the second one produces ['b']

shift()

Returns and removes the first element from the map.

public function shift()

• @return mixed|null Value from map or null if not found

Examples:

Map::from( ['a', 'b'] )->shift();
Map::from( [] )->shift();

Results:

The first example returns "a" and shortens the map to ['b'] only while the second example will return NULL

Performance note:

The bigger the list, the higher the performance impact because shift() reindexes all existing elements. Usually, it's better to reverse() the list and pop() entries from the list afterwards if a significant number of elements should be removed from the list:

$map->reverse()->pop();

instead of

$map->shift();

shuffle()

Shuffles the elements in the map without returning a new map.

public function shuffle() : self

• @return self Updated map for fluid interface

Examples:

Map::from( [2 => 'a', 4 => 'b'] )->shuffle();

Results:

The map will contain "a" and "b" in random order and with new keys assigned

slice()

Returns a map with the slice from the original map.

public function slice( int $offset, int $length = null ) : self

• @param int $offset Number of elements to start from
• @param int $length Number of elements to return
• @return self New map

Examples:

Map::from( ['a', 'b', 'c'] )->slice( 1 );
Map::from( ['a', 'b', 'c'] )->slice( 1, 1 );
Map::from( ['a', 'b', 'c', 'd'] )->slice( -2, -1 );

Results:

The first example will return ['b', 'c'] and the second one ['b'] only. The third example returns ['c'] because the slice starts at the second last value and ends before the last value.

The rules for offsets are:

• If offset is non-negative, the sequence will start at that offset
• If offset is negative, the sequence will start that far from the end

Similar for the length:

• If length is given and is positive, then the sequence will have up to that many elements in it
• If the array is shorter than the length, then only the available array elements will be present
• If length is given and is negative then the sequence will stop that many elements from the end
• If it is omitted, then the sequence will have everything from offset up until the end

some()

Tests if at least one of the elements in the list is part of the map.

public function some( iterable $list, bool $strict = false ) : bool

• @param iterable $list List of elements to test the map agains
• @param bool $strict TRUE to check the type too, using FALSE '1' and 1 will be the same
• @return bool TRUE if at least one element is available in map, FALSE if the map contains none of them

Examples:

Map::from( ['a', 'b'] )->some( ['a', 'c'] );
Map::from( ['a', 'b'] )->some( ['c', 'd'] );
Map::from( ['1', '2'] )->some( [2], true );

Results:

The first example will return TRUE while the second and third one will return FALSE

sort()

Sorts all elements without maintaining the key association.

public function sort( int $options = SORT_REGULAR ) : self

• @param int $options Sort options for sort()
• @return self Updated map for fluid interface

Examples:

Map::from( ['a' => 1, 'b' => 0] )->sort();
Map::from( [0 => 'b', 1 => 'a'] )->sort();

Results:

[0 => 0, 1 => 1]
[0 => 'a', 1 => 'b']

The parameter modifies how the values are compared. Possible parameter values are:

• SORT_REGULAR : compare elements normally (don't change types)
• SORT_NUMERIC : compare elements numerically
• SORT_STRING : compare elements as strings
• SORT_LOCALE_STRING : compare elements as strings, based on the current locale or changed by setlocale()
• SORT_NATURAL : compare elements as strings using "natural ordering" like natsort()
• SORT_FLAG_CASE : use SORT_STRING|SORT_FLAG_CASE and SORT_NATURAL|SORT_FLAG_CASE to sort strings case-insensitively

The keys aren't preserved and elements get a new index. No new map is created.

splice()

Removes a portion of the map and replace it with the given replacement, then return the updated map.

public function splice( int $offset, int $length = null, $replacement = [] ) : self

• @param int $offset Number of elements to start from
• @param int|null $length Number of elements to remove, NULL for all
• @param mixed $replacement List of elements to insert
• @return self New map

Examples:

Map::from( ['a', 'b', 'c'] )->splice( 1 );
Map::from( ['a', 'b', 'c'] )->splice( 1, 1, ['x', 'y'] );

Results:

The first example removes all entries after "a", so only ['a'] will be left in the map and ['b', 'c'] is returned. The second example replaces/returns "b" (start at 1, length 1) with ['x', 'y'] so the new map will contain ['a', 'x', 'y', 'c'] afterwards.

The rules for offsets are:

• If offset is non-negative, the sequence will start at that offset
• If offset is negative, the sequence will start that far from the end

Similar for the length:

• If length is given and is positive, then the sequence will have up to that many elements in it
• If the array is shorter than the length, then only the available array elements will be present
• If length is given and is negative then the sequence will stop that many elements from the end
• If it is omitted, then the sequence will have everything from offset up until the end

split()

Creates a new map with the string splitted by the delimiter.

public static function split( string $delimiter, string $str ) : self

• @param string $str String to split
• @param string $delimiter Delimiter character or string
• @return self New map with splitted parts

Examples:

Map::split( 'a,b,c' );
Map::split( 'a a<-->b b<-->c c', '<-->' );
Map::split( 'string', '' );

Results:

['a', 'b', 'c']
['a a', 'b b', 'c c']
['s', 't', 'r', 'i', 'n', 'g']

toArray()

Returns the elements as a plain array.

public function toArray() : array

• @return array Plain array

toJson()

Returns the elements encoded as JSON string.

public function toJson( int $options = 0 ) : string

• @param int $options Combination of JSON_* constants
• @return string Array encoded as JSON string

There are several options available to modify the JSON output: https://www.php.net/manual/en/function.json-encode.php The parameter can be a single JSON_* constant or a bitmask of several constants combine by bitwise OR (|), e.g.:

 JSON_FORCE_OBJECT|JSON_HEX_QUOT

toUrl()

Creates a HTTP query string from the map elements.

public function toUrl() : string

• @return string Parameter string for GET requests

Examples:

Map::from( ['a' => 1, 'b' => 2] )->toUrl();
Map::from( ['a' => ['b' => 'abc', 'c' => 'def'], 'd' => 123] )->toUrl();

Results:

a=1&b=2
a%5Bb%5D=abc&a%5Bc%5D=def&d=123

uasort()

Sorts all elements using a callback and maintains the key association.

public function uasort( callable $callback ) : self

• @param callable $callback Function with (itemA, itemB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self Updated map for fluid interface

The given callback will be used to compare the values. The callback must accept two parameters (item A and B) and must return -1 if item A is smaller than item B, 0 if both are equal and 1 if item A is greater than item B. Both, a method name and an anonymous function can be passed.

Examples:

Map::from( ['a' => 'B', 'b' => 'a'] )->uasort( 'strcasecmp' );
Map::from( ['a' => 'B', 'b' => 'a'] )->uasort( function( $itemA, $itemB ) {
    return strtolower( $itemA ) <=> strtolower( $itemB );
} );

Results:

['b' => 'a', 'a' => 'B']
['b' => 'a', 'a' => 'B']

The keys are preserved using this method and no new map is created.

uksort()

Sorts the map elements by their keys using a callback.

public function uksort( callable $callback ) : self

• @param callable $callback Function with (keyA, keyB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self Updated map for fluid interface

The given callback will be used to compare the keys. The callback must accept two parameters (key A and B) and must return -1 if key A is smaller than key B, 0 if both are equal and 1 if key A is greater than key B. Both, a method name and an anonymous function can be passed.

Examples:

Map::from( ['B' => 'a', 'a' => 'b'] )->uksort( 'strcasecmp' );
Map::from( ['B' => 'a', 'a' => 'b'] )->uksort( function( $keyA, $keyB ) {
    return strtolower( $keyA ) <=> strtolower( $keyB );
} );

Results:

['a' => 'b', 'B' => 'a']
['a' => 'b', 'B' => 'a']

The keys are preserved using this method and no new map is created.

union()

Builds a union of the elements and the given elements without returning a new map. Existing keys in the map will not be overwritten

public function union( iterable $elements ) : self

• @param iterable $elements List of elements
• @return self Updated map for fluid interface

Examples:

Map::from( [0 => 'a', 1 => 'b'] )->union( [0 => 'c'] );
Map::from( ['a' => 1, 'b' => 2] )->union( ['c' => 1] );

Results:

The first example will result in [0 => 'a', 1 => 'b'] because the key 0 isn't overwritten. In the second example, the result will be a combined list: ['a' => 1, 'b' => 2, 'c' => 1].

If list entries should be overwritten, please use merge() instead!

unique()

Returns only unique elements from the map in a new map

public function unique() : self

• @return self New map

Examples:

Map::from( [0 => 'a', 1 => 'b', 2 => 'b', 3 => 'c'] )->unique();

Results:

A new map with [0 => 'a', 1 => 'b', 3 => 'c'] as content

Two elements are condidered equal if comparing their string representions returns TRUE:

(string) $elem1 === (string) $elem2

The keys of the elements are preserved in the new map.

unshift()

Pushes an element onto the beginning of the map without returning a new map.

public function unshift( $value, $key = null ) : self

• @param mixed $value Item to add at the beginning
• @param mixed $key Key for the item
• @return self Same map for fluid interface

Examples:

Map::from( ['a', 'b'] )->unshift( 'd' );
Map::from( ['a', 'b'] )->unshift( 'd', 'first' );

Results:

The first example will result in ['d', 'a', 'b'] while the second one will produce ['first' => 'd', 0 => 'a', 1 => 'b'].

usort()

Sorts all elements using a callback without maintaining the key association.

public function usort( callable $callback ) : self

• @param callable $callback Function with (itemA, itemB) parameters and returns -1 (<), 0 (=) and 1 (>)
• @return self Updated map for fluid interface

The given callback will be used to compare the values. The callback must accept two parameters (item A and B) and must return -1 if item A is smaller than item B, 0 if both are equal and 1 if item A is greater than item B. Both, a method name and an anonymous function can be passed.

Examples:

Map::from( ['a' => 'B', 'b' => 'a'] )->usort( 'strcasecmp' );
Map::from( ['a' => 'B', 'b' => 'a'] )->usort( function( $itemA, $itemB ) {
    return strtolower( $itemA ) <=> strtolower( $itemB );
} );

Results:

[0 => 'a', 1 => 'B']
[0 => 'a', 1 => 'B']

The keys aren't preserved and elements get a new index. No new map is created.

Performance note:

The bigger the list, the higher the performance impact because unshift() needs to create a new list and copies all existing elements to the new array. Usually, it's better to push() new entries at the end and reverse() the list afterwards:

$map->push( 'a' )->push( 'b' )->reverse();

instead of

$map->unshift( 'a' )->unshift( 'b' );

values()

Resets the keys and return the values in a new map.

public function values() : self

• @return self New map of the values

Examples:

Map::from( ['x' => 'b', 2 => 'a', 'c'] )->values();

Results:

A new map with [0 => 'b', 1 => 'a', 2 => 'c'] as content

walk()

Applies the given callback to all elements.

To change the values of the Map, specify the value parameter as reference (&$value). You can only change the values but not the keys nor the array structure.

public function walk( callable $callback, $data = null, bool $recursive = true ) : self

• @param callable $callback Function with (item, key, data) parameters
• @param mixed $data Arbitrary data that will be passed to the callback as third parameter
• @param bool $recursive TRUE to traverse sub-arrays recursively (default), FALSE to iterate Map elements only
• @return self Map for fluid interface

Examples:

Map::from( ['a', 'B', ['c', 'd'], 'e'] )->walk( function( &$value ) {
    $value = strtoupper( $value );
} );
Map::from( [66 => 'B', 97 => 'a'] )->walk( function( $value, $key ) {
    echo 'ASCII ' . $key . ' is ' . $value . "\n";
} );
Map::from( [1, 2, 3] )->walk( function( &$value, $key, $data ) {
    $value = $data[$value] ?? $value;
}, [1 => 'one', 2 => 'two'] );

Results:

The first example will change the Map elements to:

   ['A', 'B', ['C', 'D'], 'E']

The output of the second one will be:

  ASCII 66 is B
  ASCII 97 is a

The last example changes the Map elements to:

  ['one', 'two', 3]

By default, Map elements which are arrays will be traversed recursively. To iterate over the Map elements only, pass FALSE as third parameter.

Custom methods

Most of the time, it's enough to pass an anonymous function to the pipe() method to implement custom functionality in map objects:

Map::from( ['a', 'b'] )->pipe( function( $map ) {
    return strrev( $map->join( '-' ) );
} );

If you need some functionality more often and at different places in your source code, than it's better to register a custom method once and only call it everywhere:

Map::method( 'strrev', function( $sep ) {
    return strrev( join( '-', $this->list ) );
} );
Map::from( ['a', 'b'] )->strrev( '-' );

Make sure, you register the method before using it. You can pass arbitrary parameters to your function and it has access to the internas of the map. Thus, your function can use $this to call all available methods:

Map::method( 'notInBoth', function( iterable $elements ) {
    return new self( $this->diff( $elements ) + Map::from( $elements )->diff( $this->items ) );
} );

Your custom method has access to $this->items array which contains the map elements and can also use the internal getArray( iterable $list ) method to convert iterable parameters (arrays, generators and objects implementing \Traversable) to plain arrays:

Map::method( 'combine', function( iterable $keys ) {
    return new self( array_combine( $this->getArray( $keys ), $this-items ) );
} );

Performance

The performance most methods only depends on the array_* function that are used internally by the Map class. If the methods of the Map class contains additional code, it's optimized to be as fast as possible.

Creating Map vs. array

Creating an map object with an array instead of creating a plain array only is significantly slower (ca. 10x) but in absolute values we are talking about nano seconds. It will only get notable if you create 10,000 map objects instead of 10,000 arrays. Then, creating maps will last ca. 10ms longer.

Usually, this isn't much of a problem because applications create arrays with lots of elements instead of 10,000+ arrays. Nevertheless, if your application creates a very large number of arrays within one area, you should think about avoiding map objects in that area.

If you use the map() function or Map::from() to create map objects, then be aware that this adds another function call. Using these methods for creating the map object lasts around 1.1x resp. 1.3x compared to the time for new Map(). Conclusion: Using new Map() is fastest and map() is faster than Map::from().

Populating Map vs. array

Adding an element to a Map object using $map[] = 'a' is ca. 5x slower than doing the same on a plain array. This is because the method offsetSet() will be called instead of adding the new element to the array directly. This applies to the $map->push( 'a' ) method too.

When creating arrays in loops, you should populate the array first and then create a Map object from the the array:

$list = [];
for( $i = 0; $i < 1000; $i++ ) {
	$list[] = $i;
}
$map = map( $list );

The array is NOT copied when creating the Map object so there's virtually no performance loss using the Map afterwards.

Using Map methods vs. language constructs

Language constructs such as empty(), count() or isset() are faster than calling a method and using $map->isEmpty() or $map->count() is ca. 4x slower.

Again, we are talking about nano seconds. For 10,000 calls to empty( $array ) compared to $map->isEmpty(), the costs are around 4ms in total.

Using Map methods vs. array_* functions

Using the Map methods instead of the array_* functions adds an additional method call. Internally, the Map objects uses the same array_* functions but offers a much more usable interface.

The time for the additional method call is almost neglectable because the array_* methods needs much longer to perform the operation on the array elements depending on the size of the array.

Using anonymous functions

Several Map methods support passing an anonymous function that is applied to every element of the map. PHP needs some time to call the passed function and to execute its code. Depending on the number of elements, this may have a significant impact on performance!

The pipe() method of the Map object is an exception because it receives the whole map object instead of each element separately. Its performance mainly depends on the implemented code:

$map->pipe( function( Map $map ) {
	// perform operations on the map
} );

Using shift() and unshift()

Both methods are costly, especially on large arrays. The used array_shift() and array_unshift() functions will reindex all numerical keys of the array.

If you want to reduce or create a large list of elements from the beginning in an iterative way, you should use reverse() and pop()/push() instead of shift() and unshift():

$map->reverse()->pop(); // use pop() until it returns NULL
$map->push( 'z' )->push( 'y' )->push( 'x' )->reverse(); // use push() for adding