Vector

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

Vector is a stack-like collection

HHVM provides a native implementation for this class. The PHP class definition below is not actually used at run time; it is simply provided for the typechecker and for developer reference.

Like all objects in PHP, Vectors have reference-like semantics. When a caller passes a Vector to a callee, the callee can modify the Vector and the caller will see the changes. Vectors do not have "copy-on-write" semantics.

Vectors only support integer keys. If a non-integer key is used, an exception will be thrown.

Vectors support $m[$k] style syntax for getting and setting values by key. Vectors also support isset($m[$k]) and empty($m[$k]) syntax, and they provide similar semantics as arrays. Elements can be added to a Vector using $m[] = .. syntax.

Vectors do not support iterating while new elements are being added or elements are being removed. When a new element is added or removed, all iterators that point to the Vector shall be considered invalid.

Guides

• Introduction
• Classes

Interface Synopsis

namespace HH;

final class Vector implements \MutableVector<Tv> {...}

Public Methods

• ::fromArray(darray<arraykey, Tv> $arr): Vector<Tv>
  Returns a Vector containing the values from the specified array
• ::fromItems(?Traversable<Tv> $iterable): Vector<Tv>
  Creates a Vector from the given Traversable, or an empty Vector if null is passed
• ::fromKeysOf<Tk as arraykey>(?KeyedContainer<Tk, mixed> $container): Vector<Tk>
  Creates a Vector from the keys of the specified container
• ->__construct(?Traversable<Tv> $iterable = NULL): void
  Creates a Vector from the given Traversable, or an empty Vector if null is passed
• ->__toString(): string
  Returns the string version of the current Vector, which is "Vector"
• ->add(Tv $value): Vector<Tv>
  Appends a value to the end of the current Vector, assigning it the next available integer key
• ->addAll(?Traversable<Tv> $iterable): Vector<Tv>
  For every element in the provided Traversable, append a value into this Vector, assigning the next available integer key for each
• ->addAllKeysOf(?KeyedContainer<Tv, mixed> $container): Vector<Tv>
  Adds the keys of the specified container to the current Vector
• ->append(mixed $value): this
• ->at(int $key): Tv
  Returns the value at the specified key in the current Vector
• ->clear(): Vector<Tv>
  Removes all the elements from the current Vector
• ->concat<Tu super Tv>(Traversable<Tu> $traversable): Vector<Tu>
  Returns a Vector that is the concatenation of the values of the current Vector and the values of the provided Traversable
• ->contains(mixed $key): bool
  Returns true if the specified key is present in the Vector, returns false otherwise
• ->containsKey(mixed $key): bool
  Determines if the specified key is in the current Vector
• ->count(): int
  Returns the number of elements in the current Vector
• ->filter((function(Tv): bool) $callback): Vector<Tv>
  Returns a Vector containing the values of the current Vector that meet a supplied condition
• ->filterWithKey((function(int, Tv): bool) $callback): Vector<Tv>
  Returns a Vector containing the values of the current Vector that meet a supplied condition applied to its keys and values
• ->firstKey(): ?int
  Returns the first key in the current Vector
• ->firstValue(): ?Tv
  Returns the first value in the current Vector
• ->get(int $key): ?Tv
  Returns the value at the specified key in the current Vector
• ->getIterator(): KeyedIterator<int, Tv>
  Returns an iterator that points to beginning of the current Vector
• ->immutable(): ImmVector<Tv>
  Returns an immutable copy (ImmVector) of the current Vector
• ->isEmpty(): bool
  Checks if the current Vector is empty
• ->items(): Iterable<Tv>
  Returns an Iterable view of the current Vector
• ->keys(): Vector<int>
  Returns a Vector containing the keys of the current Vector
• ->lastKey(): ?int
  Returns the last key in the current Vector
• ->lastValue(): ?Tv
  Returns the last value in the current Vector
• ->lazy(): KeyedIterable<int, Tv>
  Returns a lazy, access-elements-only-when-needed view of the current Vector
• ->linearSearch(mixed $search_value): int
  Returns the index of the first element that matches the search value
• ->map<Tu>((function(Tv): Tu) $callback): Vector<Tu>
  Returns a Vector containing the results of applying an operation to each value in the current Vector
• ->mapWithKey<Tu>((function(int, Tv): Tu) $callback): Vector<Tu>
  Returns a Vector containing the results of applying an operation to each key/value pair in the current Vector
• ->pop(): Tv
  Remove the last element of the current Vector and return it
• ->removeKey(int $key): Vector<Tv>
  Removes the key/value pair with the specified key from the current Vector
• ->reserve(int $sz): void
  Reserves enough memory to accommodate a given number of elements
• ->resize(int $size, Tv $value): void
  Resize the current Vector
• ->reverse(): void
  Reverse the elements of the current Vector in place
• ->set(int $key, Tv $value): Vector<Tv>
  Stores a value into the current Vector with the specified key, overwriting the previous value associated with the key
• ->setAll(?KeyedTraversable<int, Tv> $iterable): Vector<Tv>
  For every element in the provided Traversable, stores a value into the current Vector associated with each key, overwriting the previous value associated with the key
• ->shuffle(): void
  Shuffles the values of the current Vector randomly in place
• ->skip(int $n): Vector<Tv>
  Returns a Vector containing the values after the $n-th element of the current Vector
• ->skipWhile((function(Tv): bool) $fn): Vector<Tv>
  Returns a Vector containing the values of the current Vector starting after and including the first value that produces false when passed to the specified callback
• ->slice(int $start, int $len): Vector<Tv>
  Returns a subset of the current Vector starting from a given key up to, but not including, the element at the provided length from the starting key
• ->splice(int $offset, ?int $len = NULL): void
  Splice the current Vector in place
• ->take(int $n): Vector<Tv>
  Returns a Vector containing the first $n values of the current Vector
• ->takeWhile((function(Tv): bool) $callback): Vector<Tv>
  Returns a Vector containing the values of the current Vector up to but not including the first value that produces false when passed to the specified callback
• ->toDArray(): darray<int, Tv>
• ->toImmMap(): ImmMap<int, Tv>
  Returns an immutable, integer-keyed map (ImmMap) based on the values of the current Vector
• ->toImmSet(): ImmSet<Tv>
  Returns an immutable set (ImmSet) based on the values of the current Vector
• ->toImmVector(): ImmVector<Tv>
  Returns an immutable copy (ImmVector) of the current Vector
• ->toKeysArray(): varray<int>
  Returns an array whose values are the keys from the current Vector
• ->toMap(): Map<int, Tv>
  Returns an integer-keyed Map based on the values of the current Vector
• ->toSet(): Set<Tv>
  Returns a Set based on the values of the current Vector
• ->toVArray(): varray<Tv>
  Returns a varray built from the values from this Vector
• ->toValuesArray(): varray<Tv>
  Returns an array containing the values from the current Vector
• ->toVector(): Vector<Tv>
  Returns a copy of the current Vector
• ->values(): Vector<Tv>
  Returns a Vector containing the values of the current Vector
• ->zip<Tu>(Traversable<Tu> $traversable): Vector<Pair<Tv, Tu>>
  Returns a Vector where each element is a Pair that combines the element of the current Vector and the provided Traversable