PHP Ds\Map Functions Complete Reference

A Map is a sequential collection of key-value pair which is very similar to the array. The key of a map can be of any type and it is unique. If any value added to the same key in a Map then the map value will replace. It is the efficient Data Structure in PHP 7 to provide the alternative of an array. 

Requirements: PHP 7 is required for both extension and the compatibility polyfill.

Installation: The easiest way to install data structure by using PECL extension.

pecl install ds

Syntax:

public Ds\Map::functionName()

Example: Below programs illustrate the Ds\Map::filter() function in PHP:

PHP

<?php
// PHP program to illustrate the filter()
// function of Ds\map

// Creating a Map
$map = new \Ds\Map([
    1 => "Welcome",
    2 => "to",
    3 => "Geeks",
    4 => "for",
    5 => "Geeks"]);


// Display new sequence using filter function
var_dump($map->filter(function($key, $val) {
    return $key % 3 == 0;
}));

?>

Output:

object(Ds\Map)#3 (1) {
  [0]=>
  object(Ds\Pair)#2 (2) {
    ["key"]=>
    int(3)
    ["value"]=>
    string(5) "Geeks"
  }
}

Complete list of data structure DS\Map:

PHP Ds\Map Functions	Description
allocate()	Allocate enough memory for required capacity.
apply()	Apply a specific operation to all of the elements present in the map
capacity()	Return the current capacity of the map.
clear()	It is used to clear a Map object.
__construct()	It is used to creates a new instance.
copy()	Get a shallow copy of the specified Map instance.
count()	Count the number of elements present in the Map.
diff()	Create a map using the key which contains the elements of the first map which are not present in another map.
filter()	Create a new map using the filter function.
first()	Get the first key-value pair from the Map instance.
get()	Return the value of the given key.
hasKey()	Check whether a given Key is present in the Map object or not.
hasValue()	Determines whether the map contains a given value
intersect()	Create a new map that contains the intersection with another map.
isEmpty()	Check whether a given Map is empty or not.
keys()	Set of keys of the current Map instance.
ksort()	Sort the map element in-place by key.
ksorted()	Returns a copy which is sorted by key.
last()	Find and get the last key-value pair from a Map object.
map()	Apply a callback function to a Map object.
merge()	Return the result of adding all given associations.
pairs()	Get all of the pairs from the specified Map instance.
put()	It is used to associates a key with a value.
putAll()	Associate all key-value pairs of a traversable object or array.
reduce()	Reduce the map to a single value by applying operations using the callback function.
reverse()	In-place reverse the elements of a specified Map instance.
reversed()	Get a copy of the reverse of elements of a specified Map instance.
skip()	Return the pair at a given positional index.
slice()	Get a subset of the specified Map instance.
sort()	In-place sort the elements of a specified Map instance according to the values.
sorted()	Get a copy of the specified Map instance sorted according to the values.
sum()	Get the sum of all of the values present in the Map instance.
toArray()	Get an array generated by converting the Map instance into an Array.
union()	Create a new map that contains the union of two maps.
values()	Return a sequence of the map’s values.
xor()	Create a new map that contains the value either in the first map or the second map but not both.