JavaScript Float32Array : Object

constructor

Float32Array is similar to an Array where each item is a 32 bit (4 byte) floating point number. Float32Arrays cannot change size after creation.

Spec

Constructors

new Float32Array(length : Number) : Float32Array

Creates a new Float32Array of the specified length where each item starts out as 0

Example:

var x = new Float32Array(2);
x[0] = 17;
console.log(x[0]);
console.log(x[1]);
console.log(x.length);

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Results:

new Float32Array(array : Array) : Float32Array

Creates a new Float32Array and copies the items of array into this. The copied items are converted to 32 bit floats before being stored in this.

Example:

var x = new Float32Array([17, -45.3]);
console.log(x[0]);
console.log(x[1]);
console.log(x.length);

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Results:

new Float32Array(array : Float32Array) : Float32Array

Creates a new Float32Array and copies the items of array into this. array can be any of the typed array types and the copied items will be converted to 32 bit floats before being stored in this.

Example:

var x = new Float32Array([17, -45.3]);
var y = new Float32Array(x);
console.log(x[0]);
console.log(x[1]);
console.log(x.length);
x[0] = -2;
console.log(y[0]); // y is not modified

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Results:

new Float32Array(buffer : ArrayBuffer, [byteOffset = 0 : Number, [length : Number]]) : Float32Array

Creates a view on top of the specified buffer starting at byteOffset of length items. Changes to the items in this actual affect the underlying buffer, and vice versa. byteOffset must be a multiple of 4. (Use DataView for unaligned data.) If length is not specified, the returned Float32Array's buffer.length - byteOffset must be a multiple of 4 and this.length will be (buffer.length - byteOffset) / 4.

Example:

var buffer = new ArrayBuffer(12);
var x = new Float32Array(buffer, 0, 2);
// Make another view of last 4 bytes of the buffer
var y = new Float32Array(buffer, 4, 1);
x[1] = 7;
console.log(y[0]); // y is a live view on the buffer

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Results:

Instance Properties

buffer : ArrayBuffer

Returns the underlying buffer for this Float32Array.

Example:

var buffer = new ArrayBuffer(12);
var x = new Float32Array(buffer, 0, 2);
var y = new Float32Array(x.buffer, 4, 2);
console.log(x.buffer === y.buffer);

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Results:

byteLength : Number

The length of this in bytes.

Example:

var buffer = new ArrayBuffer(12);
var x = new Float32Array(buffer, 4, 2);
console.log(x.byteLength); 
console.log(x.length * Float32Array.BYTES_PER_ELEMENT);

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Results:

byteOffset : Number

The offset into this.buffer where the 0th item is stored.

Example:

var buffer = new ArrayBuffer(12);
var x = new Float32Array(buffer, 4, 2);
console.log(x.byteOffset);

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Results:

length : Number

The number of elements in this. It is 1 greater than the index of the last item.

Example:

var x = new Float32Array(10);
console.log(x.length);

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Results:

Instance Methods

set 2 variants

set(array : Array, [offset = 0 : Number]) : undefined

Copies items from array into this starting at this[offset]. Copied items are converted to 32 bit floats before storing in this.

Example:

var x = new Float32Array(10);
x.set([18, 93, 42], 3);
console.log(x[3]);
console.log(x[4]);
console.log(x[5]);

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Results:

set(array : Float32Array, [offset = 0 : Number]) : undefined

Copies items from array into this starting at this[offset]. array can be any of the typed array types and the copied items will be converted to 32 bit floats before storing in this.

Example:

var x = new Float32Array(10);
x.set(new Float32Array([18, 93, 42]), 3);
console.log(x[3]);
console.log(x[4]);
console.log(x[5]);

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Results:

subarray(begin : Number, [end : Number]) : Float32Array

Returns a new Float32Array that is a view on top of this containing items this[begin], this[begin + 1], ..., this[end - 1]. The 0th item in the returned array in the same memory location as this[begin]. If end is not specified, this.length is used.

Example:

var x = new Float32Array([0, 1, 2, 3, 4, 5]); // length=6
var y = x.subarray(2, 5);
console.log(y.length);
console.log(y[0]);
console.log(y[1]);
y[0] = -1;
console.log(x[2]);

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Results:

Float32Array Properties

BYTES_PER_ELEMENT : Number

Returns the size in bytes of an item in an Float32Array.

Example:

console.log(Float32Array.BYTES_PER_ELEMENT);

Run

Results:

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