Float64Array
Объект Float64Array
представляет типизированный массив 64-битных чисел с плавающей запятой (соответствует типу double
в языке C) с платформо-зависимым порядком байт.Если необходим контроль за порядком байт, то вместо этого объекта используйте DataView
. Содержимое инициализируется значением 0
. Создав экземпляр Float64Array
, можно получить доступ к элементам массива, используя методы объекта или стандартный синтаксис доступа к элементу массива по его индексу (с помощью скобочной нотации - квадратные скобки).
Syntax
new Float64Array(); // new in ES2017 new Float64Array(length); new Float64Array(typedArray); new Float64Array(object); new Float64Array(buffer [, byteOffset [, length]]);
For more information about the constructor syntax and the parameters, see TypedArray.
Properties
Float64Array.BYTES_PER_ELEMENT
-
Returns a number value of the element size.
8
in the case of anFloat64Array
. - Float64Array.length
-
Static length property whose value is 0. For the actual length (number of elements), see
Float64Array.prototype.length
(en-US). Float64Array.name
(en-US)-
Returns the string value of the constructor name. In the case of the
Float64Array
type: "Float64Array". Float64Array.prototype
(en-US)-
Prototype for the TypedArray objects.
Methods
Float64Array.from()
(en-US)-
Creates a new
Float64Array
from an array-like or iterable object. See alsoArray.from()
. Float64Array.of()
(en-US)-
Creates a new
Float64Array
with a variable number of arguments. See alsoArray.of()
.
Float64Array
prototype
All Float64Array
objects inherit from %TypedArray%.prototype
(en-US).
Properties
Float64Array.prototype.constructor
-
Returns the function that created an instance's prototype. This is the
Float64Array
constructor by default. Float64Array.prototype.buffer
(en-US) Только для чтения-
Returns the
ArrayBuffer
referenced by theFloat64Array
Fixed at construction time and thus read only. Float64Array.prototype.byteLength
(en-US) Только для чтения-
Returns the length (in bytes) of the
Float64Array
from the start of itsArrayBuffer
. Fixed at construction time and thus read only. Float64Array.prototype.byteOffset
(en-US) Только для чтения-
Returns the offset (in bytes) of the
Float64Array
from the start of itsArrayBuffer
. Fixed at construction time and thus read only. Float64Array.prototype.length
(en-US) Только для чтения-
Returns the number of elements hold in the
Float64Array
. Fixed at construction time and thus read only.
Methods
Float64Array.prototype.copyWithin()
(en-US)-
Copies a sequence of array elements within the array. See also
Array.prototype.copyWithin()
. Float64Array.prototype.entries()
(en-US)-
Returns a new
Array Iterator
object that contains the key/value pairs for each index in the array. See alsoArray.prototype.entries()
. Float64Array.prototype.every()
(en-US)-
Tests whether all elements in the array pass the test provided by a function. See also
Array.prototype.every()
. Float64Array.prototype.fill()
(en-US)-
Fills all the elements of an array from a start index to an end index with a static value. See also
Array.prototype.fill()
. Float64Array.prototype.filter()
(en-US)-
Creates a new array with all of the elements of this array for which the provided filtering function returns true. See also
Array.prototype.filter()
. Float64Array.prototype.find()
(en-US)-
Returns the found value in the array, if an element in the array satisfies the provided testing function or
undefined
if not found. See alsoArray.prototype.find()
. Float64Array.prototype.findIndex()
(en-US)-
Returns the found index in the array, if an element in the array satisfies the provided testing function or -1 if not found. See also
Array.prototype.findIndex()
. Float64Array.prototype.forEach()
(en-US)-
Calls a function for each element in the array. See also
Array.prototype.forEach()
. Float64Array.prototype.includes()
(en-US) Экспериментальная возможность-
Determines whether a typed array includes a certain element, returning
true
orfalse
as appropriate. See alsoArray.prototype.includes()
. Float64Array.prototype.indexOf()
(en-US)-
Returns the first (least) index of an element within the array equal to the specified value, or -1 if none is found. See also
Array.prototype.indexOf()
. Float64Array.prototype.join()
-
Joins all elements of an array into a string. See also
Array.prototype.join()
. Float64Array.prototype.keys()
(en-US)-
Returns a new
Array Iterator
that contains the keys for each index in the array. See alsoArray.prototype.keys()
. Float64Array.prototype.lastIndexOf()
(en-US)-
Returns the last (greatest) index of an element within the array equal to the specified value, or -1 if none is found. See also
Array.prototype.lastIndexOf()
. Float64Array.prototype.map()
(en-US)-
Creates a new array with the results of calling a provided function on every element in this array. See also
Array.prototype.map()
. Float64Array.prototype.move()
Non-standard Не реализовано-
Former non-standard version of
Float64Array.prototype.copyWithin()
(en-US). Float64Array.prototype.reduce()
(en-US)-
Apply a function against an accumulator and each value of the array (from left-to-right) as to reduce it to a single value. See also
Array.prototype.reduce()
. Float64Array.prototype.reduceRight()
(en-US)-
Apply a function against an accumulator and each value of the array (from right-to-left) as to reduce it to a single value. See also
Array.prototype.reduceRight()
. Float64Array.prototype.reverse()
(en-US)-
Reverses the order of the elements of an array — the first becomes the last, and the last becomes the first. See also
Array.prototype.reverse()
. Float64Array.prototype.set()
-
Stores multiple values in the typed array, reading input values from a specified array.
Float64Array.prototype.slice()
(en-US)-
Extracts a section of an array and returns a new array. See also
Array.prototype.slice()
. Float64Array.prototype.some()
(en-US)-
Returns true if at least one element in this array satisfies the provided testing function. See also
Array.prototype.some()
. Float64Array.prototype.sort()
(en-US)-
Sorts the elements of an array in place and returns the array. See also
Array.prototype.sort()
. Float64Array.prototype.subarray()
(en-US)-
Returns a new
Float64Array
from the given start and end element index. Float64Array.prototype.values()
(en-US)-
Returns a new
Array Iterator
object that contains the values for each index in the array. See alsoArray.prototype.values()
. Float64Array.prototype.toLocaleString()
(en-US)-
Returns a localized string representing the array and its elements. See also
Array.prototype.toLocaleString()
. Float64Array.prototype.toString()
(en-US)-
Returns a string representing the array and its elements. See also
Array.prototype.toString()
. Float64Array.prototype[@@iterator]()
(en-US)-
Returns a new
Array Iterator
object that contains the values for each index in the array.
Examples
Different ways to create a Float64Array
:
js
// From a length
var float64 = new Float64Array(2);
float64[0] = 42;
console.log(float64[0]); // 42
console.log(float64.length); // 2
console.log(float64.BYTES_PER_ELEMENT); // 8
// From an array
var arr = new Float64Array([21, 31]);
console.log(arr[1]); // 31
// From another TypedArray
var x = new Float64Array([21, 31]);
var y = new Float64Array(x);
console.log(y[0]); // 21
// From an ArrayBuffer
var buffer = new ArrayBuffer(32);
var z = new Float64Array(buffer, 0, 4);
// From an iterable
var iterable = (function* () {
yield* [1, 2, 3];
})();
var float64 = new Float64Array(iterable);
// Float64Array[1, 2, 3]
Specifications
Specification | Status | Comment |
---|---|---|
Typed Array Specification | Устаревшая | Superseded by ECMAScript 2015. |
ECMAScript 2015 (6th Edition, ECMA-262) Определение 'TypedArray constructors' в этой спецификации. |
Стандарт | Initial definition in an ECMA standard. Specified that new is required. |
ECMAScript (ECMA-262) Определение 'TypedArray constructors' в этой спецификации. |
Живой стандарт | ECMAScript 2017 changed the Float64Array constructor to use the ToIndex operation and allows constructors with no arguments. |
Browser compatibility
BCD tables only load in the browser
Compatibility notes
Starting with ECMAScript 2015, Float64Array
constructors require to be constructed with a new
operator. Calling a Float64Array
constructor as a function without new
, will throw a TypeError
from now on.
js
var dv = Float64Array([1, 2, 3]);
// TypeError: calling a builtin Float64Array constructor
// without new is forbidden
js
var dv = new Float64Array([1, 2, 3]);