PHP - Set Functions

Set is a sequence of unique values, and this implementation can use the same hash table as Ds\Map where the values are used as keys, and the mapped value is ignored.

Strengths

Values can be any type, including objects.
Supports array syntax (square brackets).
Insertion order is preserved.
Automatically frees allocated memory when its size drops low enough.
add(), remove() and contains() are all O(1).

Weaknesses

Doesn’t support push(), pop(), insert(), shift(), or unshift().
get() is O(n) if there are deleted values in the buffer before the accessed index, O(1) otherwise.

Class synopsis

Ds\Set implements Ds\Collection {
   /* Constants */
   const int MIN_CAPACITY = 16 ;

   /* Methods */
   public void add([ mixed $...values ] )
   public void allocate( int $capacity )
   public int capacity( void )
   public void clear( void )
   public bool contains([ mixed $...values ] )
   public Ds\Set copy( void )
   public Ds\Set diff( Ds\Set $set )
   public Ds\Set filter([ callable $callback ] )
   public void first( void )
   public mixed get( int $index )
   public Ds\Set intersect( Ds\Set $set )
   public bool isEmpty( void )
   public string join([ string $glue ] )
   public void last( void )
   public Ds\Set merge( mixed $values )
   public mixed reduce( callable $callback [, mixed $initial ] )
   public void remove([ mixed $...values ] )
   public void reverse( void )
   public Ds\Set reversed( void )
   public Ds\Set slice( int $index [, int $length ] )
   public void sort([ callable $comparator ] )
   public Ds\Set sorted([ callable $comparator ] )
   public number sum( void ) 
   public array toArray( void )
   public Ds\Set union( Ds\Set $set )
   public Ds\Set xor( Ds\Set $set )
}

Predefined Constants

Ds\Set::MIN_CAPACITY

Sr.No	Function & Description
1	Ds\Set::allocate() This Function can allocate enough memory for the required capacity.
2	Ds\Set::add() This Function can can add values to the set.
3	Ds\Set::capacity() This Function can return the current capacity.
4	Ds\Set::clear() This Function can remove the all values.
5	Ds\Set::__construct() This Function can create a new instance.
6	Ds\Set::contains() This Function can determine if the set contains all values.
7	Ds\Set::copy() This Function can return a shallow copy of the set.
8	Ds\Set::count This Function can be used to count the number of values present in a set, and also referred to as the size of a set instance.
9	Ds\Set::diff() This Function can create a new set by using the values that aren't in another set.
10	Ds\Sequence::filter() This Function can create the new set by using a callable to determine which values to include.
11	Ds\Set::first() This Function can return the first value in a set.
12	Ds\Set::get() This Function can return the value at a given index.
13	Ds\Set::intersect() This Function can create a new set by intersecting the values with another set.
14	Ds\Set::isEmpty() This Function can return whether the set is empty.
15	Ds\Set::join() This Function can join all values together as a string.
16	Ds\Set::jsonSerialize() This Function can return a representation that can be converted to JSON.
17	Ds\Set::last() This Function can return the last value in a set.
18	Ds\Set::merge() This Function can return the result of adding all given values to a set.
19	Ds\Set::reduce() This Function can reduce a set to single value by using callback function.
20	Ds\Set::remove() This Function can remove all given values from the set.
21	Ds\Set::reverse() This Function can can reverse a set in-place.
22	Ds\Set::reversed() This Function can return a reversed copy.
23	Ds\Set::slice() This Function can return the sub-set of a given range.
24	Ds\Set::sort() This Function can sort a set in-place.
25	Ds\Set::sorted() This Function can return a sorted copy.
26	Ds\Set::sum() This Function can return the sum of all values in a set.
27	Ds\Set::toArray() This Function can convert a set to an array.
28	Ds\Set::union() This Function can create a new set by using values from the current instance and another set.
29	Ds\Set::xor() This Function can create a new set by using the values in the current instance and another set but not in both.

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