struct StaticArray(T, N)

Overview

A fixed-size, stack allocated array.

StaticArray is a generic type with type argument T specifying the type of its elements and N the fixed size. For example StaticArray(Int32, 3) is a static array of Int32 with three elements.

Instantiations of this static array type:

StaticArray(Int32, 3).new(42)           # => StaticArray[42, 42, 42]
StaticArray(Int32, 3).new { |i| i * 2 } # => StaticArray[0, 2, 4]
StaticArray[0, 8, 15]                   # => StaticArray[0, 8, 15]

This type can also be expressed as Int32[3] (only in type grammar). A typical use case is in combination with uninitialized:

ints = uninitialized Int32[3]
ints[0] = 0
ints[1] = 8
ints[2] = 15

For number types there is also Number.static_array which can be used to initialize a static array:

Int32.static_array(0, 8, 15) # => StaticArray[0, 8, 15]

The generic argument type N is a special case in the type grammar as it doesn't specify a type but a size. Its value can be an Int32 literal or constant.

Included Modules

Defined in:

Constructors

Instance Method Summary

Macro Summary

Instance methods inherited from module Indexable(T)

[](index : Int) [], []?(index : Int) []?, bsearch(&block : T -> Bool) bsearch, bsearch_index(&block : T, Int32 -> Bool) bsearch_index, dig(index : Int, *subindexes) dig, dig?(index : Int, *subindexes) dig?, each(*, start : Int, count : Int, &)
each(*, within range : Range, &)
each(&)
each
each
, each_index(*, start : Int, count : Int, &)
each_index(&) : Nil
each_index
each_index
, empty? empty?, equals?(other : Indexable, &)
equals?(other, &)
equals?
, fetch(index, default)
fetch(index : Int, &)
fetch
, first
first(&)
first
, first? first?, hash(hasher) hash, index(object, offset : Int = 0)
index(offset : Int = 0, &)
index
, join(separator = "") join, last
last(&)
last
, last? last?, reverse_each(&) : Nil
reverse_each
reverse_each
, rindex(offset = size - 1, &)
rindex(value, offset = size - 1)
rindex
, sample(random = Random::DEFAULT) sample, size size, to_a to_a, unsafe_fetch(index : Int) unsafe_fetch, values_at(*indexes : Int) values_at

Instance methods inherited from module Enumerable(T)

all?(&)
all?(pattern)
all?
all?
, any?(&)
any?(pattern)
any?
any?
, chunks(&block : T -> U) forall U chunks, compact_map(&) compact_map, count(&)
count(item)
count
, cycle(n, &)
cycle(&)
cycle
, each(&block : T -> _) each, each_cons(count : Int, reuse = false, &) each_cons, each_cons_pair(& : T, T -> _) : Nil each_cons_pair, each_slice(count : Int, reuse = false, &) each_slice, each_with_index(offset = 0, &) each_with_index, each_with_object(obj, &) each_with_object, find(if_none = nil, &) find, first(count : Int)
first
first
, first? first?, flat_map(&block : T -> Array(U) | Iterator(U) | U) forall U flat_map, grep(pattern) grep, group_by(&block : T -> U) forall U group_by, in_groups_of(size : Int, filled_up_with : U = nil) forall U
in_groups_of(size : Int, filled_up_with : U = nil, reuse = false, &) forall U
in_groups_of
, includes?(obj) includes?, index(&)
index(obj)
index
, index_by(&block : T -> U) forall U index_by, join(separator = "", &)
join(separator, io, &)
join(separator, io)
join(separator = "")
join
, map(&block : T -> U) forall U map, map_with_index(offset = 0, &block : T, Int32 -> U) forall U map_with_index, max max, max? max?, max_by(&block : T -> U) forall U max_by, max_by?(&block : T -> U) forall U max_by?, max_of(&block : T -> U) forall U max_of, max_of?(&block : T -> U) forall U max_of?, min min, min? min?, min_by(&block : T -> U) forall U min_by, min_by?(&block : T -> U) forall U min_by?, min_of(&block : T -> U) forall U min_of, min_of?(&block : T -> U) forall U min_of?, minmax minmax, minmax? minmax?, minmax_by(&block : T -> U) forall U minmax_by, minmax_by?(&block : T -> U) forall U minmax_by?, minmax_of(&block : T -> U) forall U minmax_of, minmax_of?(&block : T -> U) forall U minmax_of?, none?
none?(pattern)
none?(&)
none?
, one?(&)
one?(pattern)
one?
one?
, partition(&) partition, product(&)
product(initial : Number, &)
product
product(initial : Number)
product
, reduce(memo, &)
reduce(&)
reduce
, reduce?(&) reduce?, reject(&block : T -> )
reject(type : U.class) forall U
reject(pattern)
reject
, select(pattern)
select(type : U.class) forall U
select(&block : T -> )
select
, size size, skip(count : Int) skip, skip_while(&) skip_while, sum(initial)
sum
sum(initial, &)
sum(&)
sum
, take_while(&) take_while, tally : Hash(T, Int32) tally, to_a to_a, to_h
to_h(&block : T -> Tuple(K, V)) forall K, V
to_h
, to_set to_set, zip(*others : Indexable | Iterable | Iterator, &)
zip(*others : Indexable | Iterable | Iterator)
zip
, zip?(*others : Indexable | Iterable | Iterator, &)
zip?(*others : Indexable | Iterable | Iterator)
zip?

Instance methods inherited from module Iterable(T)

chunk(reuse = false, &block : T -> U) forall U chunk, chunk_while(reuse : Bool | Array(T) = false, &block : T, T -> B) forall B chunk_while, cycle(n)
cycle
cycle
, each each, each_cons(count : Int, reuse = false) each_cons, each_slice(count : Int, reuse = false) each_slice, each_with_index(offset = 0) each_with_index, each_with_object(obj) each_with_object, slice_after(reuse : Bool | Array(T) = false, &block : T -> B) forall B
slice_after(pattern, reuse : Bool | Array(T) = false)
slice_after
, slice_before(reuse : Bool | Array(T) = false, &block : T -> B) forall B
slice_before(pattern, reuse : Bool | Array(T) = false)
slice_before
, slice_when(reuse : Bool | Array(T) = false, &block : T, T -> B) forall B slice_when

Instance methods inherited from struct Value

==(other : JSON::Any)
==(other : YAML::Any)
==(other)
==
, dup dup

Instance methods inherited from class Object

!=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other)
===
, =~(other) =~, __crystal_pseudo_! : Bool __crystal_pseudo_!, __crystal_pseudo_as(type : Class) __crystal_pseudo_as, __crystal_pseudo_as?(type : Class) __crystal_pseudo_as?, __crystal_pseudo_is_a?(type : Class) : Bool __crystal_pseudo_is_a?, __crystal_pseudo_nil? : Bool __crystal_pseudo_nil?, __crystal_pseudo_responds_to?(name : Symbol) : Bool __crystal_pseudo_responds_to?, class class, dup dup, hash(hasher)
hash
hash
, in?(*values : Object) : Bool
in?(collection) : Bool
in?
, inspect : String
inspect(io : IO) : Nil
inspect
, itself itself, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, tap(&) tap, to_json
to_json(io : IO)
to_json
, to_pretty_json(indent : String = " ")
to_pretty_json(io : IO, indent : String = " ")
to_pretty_json
, to_s : String
to_s(io : IO) : Nil
to_s
, to_yaml(io : IO)
to_yaml
to_yaml
, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

Class methods inherited from class Object

from_json(string_or_io, root : String)
from_json(string_or_io)
from_json
, from_yaml(string_or_io : String | IO) from_yaml

Constructor Detail

def self.new(&block : Int32 -> T) #

Creates a new static array and invokes the block once for each index of the array, assigning the block's value in that index.

StaticArray(Int32, 3).new { |i| i * 2 } # => StaticArray[0, 2, 4]

def self.new(value : T) #

Creates a new static array filled with the given value.

StaticArray(Int32, 3).new(42) # => StaticArray[42, 42, 42]

Instance Method Detail

def ==(other : StaticArray) #

Equality. Returns true if each element in self is equal to each corresponding element in other.

array = StaticArray(Int32, 3).new 0  # => StaticArray[0, 0, 0]
array2 = StaticArray(Int32, 3).new 0 # => StaticArray[0, 0, 0]
array3 = StaticArray(Int32, 3).new 1 # => StaticArray[1, 1, 1]
array == array2                      # => true
array == array3                      # => false

def ==(other) #

Equality with another object. Always returns false.

array = StaticArray(Int32, 3).new 0 # => StaticArray[0, 0, 0]
array == nil                        # => false

def []=(index : Int, value : T) #

Sets the given value at the given index.

Negative indices can be used to start counting from the end of the array. Raises IndexError if trying to set an element outside the array's range.

array = StaticArray(Int32, 3).new { |i| i + 1 } # => StaticArray[1, 2, 3]
array[2] = 2                                    # => 2
array                                           # => StaticArray[1, 2, 2]
array[4] = 4                                    # raises IndexError

def []=(value : T) #

Fills the array by substituting all elements with the given value.

array = StaticArray(Int32, 3).new { |i| i + 1 }
array.[]= 2 # => nil
array       # => StaticArray[2, 2, 2]

def clone #

Returns a new StaticArray where each element is cloned from elements in self.


def map(&block : T -> U) forall U #

Returns a new static array where elements are mapped by the given block.

array = StaticArray[1, 2.5, "a"]
array.map &.to_s # => StaticArray["1", "2.5", "a"]

def map!(&) #

Invokes the given block for each element of self, replacing the element with the value returned by the block. Returns self.

array = StaticArray(Int32, 3).new { |i| i + 1 }
array.map! { |x| x*x } # => StaticArray[1, 4, 9]

def map_with_index(offset = 0, &block : T, Int32 -> U) forall U #

Like #map, but the block gets passed both the element and its index.

Accepts an optional offset parameter, which tells it to start counting from there.


def map_with_index!(offset = 0, &block : T, Int32 -> T) #

Like #map!, but the block gets passed both the element and its index.

Accepts an optional offset parameter, which tells it to start counting from there.


def pretty_print(pp) #

def reverse! #

Reverses the elements of this array in-place, then returns self.

array = StaticArray(Int32, 3).new { |i| i + 1 }
array.reverse! # => StaticArray[3, 2, 1]

def shuffle!(random = Random::DEFAULT) #

Modifies self by randomizing the order of elements in the array using the given random number generator. Returns self.

a = StaticArray(Int32, 3).new { |i| i + 1 } # => StaticArray[1, 2, 3]
a.shuffle!(Random.new(42))                  # => StaticArray[3, 2, 1]
a                                           # => StaticArray[3, 2, 1]

def size #

Returns the size of self

array = StaticArray(Int32, 3).new { |i| i + 1 }
array.size # => 3

def to_s(io : IO) : Nil #

Appends a string representation of this static array to the given IO.

array = StaticArray(Int32, 3).new { |i| i + 1 }
array.to_s # => "StaticArray[1, 2, 3]"

def to_slice #

Returns a slice that points to the elements of this static array. Changes made to the returned slice also affect this static array.

array = StaticArray(Int32, 3).new(2)
slice = array.to_slice # => Slice[2, 2, 2]
slice[0] = 3
array # => StaticArray[3, 2, 2]

def to_unsafe : Pointer(T) #

Returns a pointer to this static array's data.

ary = StaticArray(Int32, 3).new(42)
ary.to_unsafe[0] # => 42

def unsafe_fetch(index : Int) #
Description copied from module Indexable(T)

Returns the element at the given index, without doing any bounds check.

Indexable makes sure to invoke this method with index in 0...size, so converting negative indices to positive ones is not needed here.

Clients never invoke this method directly. Instead, they access elements with #[](index) and #[]?(index).

This method should only be directly invoked if you are absolutely sure the index is in bounds, to avoid a bounds check for a small boost of performance.


def update(index : Int, &) #

Yields the current element at the given index and updates the value at the given index with the block's value. Raises IndexError if trying to set an element outside the array's range.

array = StaticArray(Int32, 3).new { |i| i + 1 } # => StaticArray[1, 2, 3]
array.update(1) { |x| x * 2 }                   # => 4
array                                           # => StaticArray[1, 4, 3]
array.update(5) { |x| x * 2 }                   # raises IndexError

Macro Detail

macro [](*args) #

Creates a new StaticArray with the given args. The type of the static array will be the union of the type of the given args, and its size will be the number of elements in args.

ary = StaticArray[1, 'a']
ary[0]    # => 1
ary[1]    # => 'a'
ary.class # => StaticArray(Char | Int32, 2)

See also: Number.static_array.