The Set class

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Introduction

A Set is a sequence of unique values. This implementation uses the same hash table as Ds\Map, where 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

class Ds\Set implements Ds\Collection, ArrayAccess {

/* Constants */

const int MIN_CAPACITY = 16;

/* Methods */

public add(mixed ...$values): void

public allocate(int $capacity): void

public capacity(): int

public clear(): void

public contains(mixed ...$values): bool

public copy(): Ds\Set

public diff(Ds\Set $set): Ds\Set

public filter(callable $callback = ?): Ds\Set

public first(): mixed

public get(int $index): mixed

public intersect(Ds\Set $set): Ds\Set

public isEmpty(): bool

public join(string $glue = ?): string

public last(): mixed

public merge(mixed $values): Ds\Set

public reduce(callable $callback, mixed $initial = ?): mixed

public remove(mixed ...$values): void

public reverse(): void

public reversed(): Ds\Set

public slice(int $index, int $length = ?): Ds\Set

public sort(callable $comparator = ?): void

public sorted(callable $comparator = ?): Ds\Set

public sum(): int|float

public toArray(): array

public union(Ds\Set $set): Ds\Set

public xor(Ds\Set $set): Ds\Set

}

Predefined Constants

Ds\Set::MIN_CAPACITY

Changelog

Version	Description
PECL ds 1.3.0	The class now implements ArrayAccess.

Ds\Set::add — Adds values to the set
Ds\Set::allocate — Allocates enough memory for a required capacity
Ds\Set::capacity — Returns the current capacity
Ds\Set::clear — Removes all values
Ds\Set::__construct — Creates a new instance
Ds\Set::contains — Determines if the set contains all values
Ds\Set::copy — Returns a shallow copy of the set
Ds\Set::count — Returns the number of values in the set
Ds\Set::diff — Creates a new set using values that aren't in another set
Ds\Set::filter — Creates a new set using a callable to determine which values to include
Ds\Set::first — Returns the first value in the set
Ds\Set::get — Returns the value at a given index
Ds\Set::intersect — Creates a new set by intersecting values with another set
Ds\Set::isEmpty — Returns whether the set is empty
Ds\Set::join — Joins all values together as a string
Ds\Set::jsonSerialize — Returns a representation that can be converted to JSON
Ds\Set::last — Returns the last value in the set
Ds\Set::merge — Returns the result of adding all given values to the set
Ds\Set::reduce — Reduces the set to a single value using a callback function
Ds\Set::remove — Removes all given values from the set
Ds\Set::reverse — Reverses the set in-place
Ds\Set::reversed — Returns a reversed copy
Ds\Set::slice — Returns a sub-set of a given range
Ds\Set::sort — Sorts the set in-place
Ds\Set::sorted — Returns a sorted copy
Ds\Set::sum — Returns the sum of all values in the set
Ds\Set::toArray — Converts the set to an array
Ds\Set::union — Creates a new set using values from the current instance and another set
Ds\Set::xor — Creates a new set using values in either the current instance or in another set, but not in both