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Boolean array.
npm install @stdlib/array-boolAlternatively,
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var BooleanArray = require( '@stdlib/array-bool' );Creates a boolean array.
var arr = new BooleanArray();
// returns <BooleanArray>Creates a boolean array having a specified length.
var arr = new BooleanArray( 10 );
// returns <BooleanArray>
var len = arr.length;
// returns 10Creates a boolean array from another boolean array.
var arr1 = new BooleanArray( [ true, false, false, true ] );
// returns <BooleanArray>
var arr2 = new BooleanArray( arr1 );
// returns <BooleanArray>
var len = arr2.length;
// returns 4Creates a boolean array from a typed array.
var Uint8Array = require( '@stdlib/array-uint8' );
var buf = new Uint8Array( [ 1, 0, 0, 1 ] );
// returns <Uint8Array>[ 1, 0, 0, 1 ]
var arr = new BooleanArray( buf );
// returns <BooleanArray>
var len = arr.length;
// returns 4Creates a boolean array from an array-like object or iterable.
// From an array of booleans:
var arr1 = new BooleanArray( [ true, false, false, true ] );
// returns <BooleanArray>
var len = arr1.length;
// returns 4
// From an array containing non-booleans:
var arr2 = new BooleanArray( [ {}, null, '', 4 ] );
len = arr2.length;
// returns 4Returns a boolean array view of an ArrayBuffer.
var ArrayBuffer = require( '@stdlib/array-buffer' );
var buf = new ArrayBuffer( 240 );
var arr1 = new BooleanArray( buf );
// returns <BooleanArray>
var len = arr1.length;
// returns 240
var arr2 = new BooleanArray( buf, 8 );
// returns <BooleanArray>
len = arr2.length;
// returns 232
var arr3 = new BooleanArray( buf, 8, 20 );
// returns <BooleanArray>
len = arr3.length;
// returns 20Static property returning the size (in bytes) of each array element.
var nbytes = BooleanArray.BYTES_PER_ELEMENT;
// returns 1Static property returning the constructor name.
var str = BooleanArray.name;
// returns 'BooleanArray'Pointer to the underlying data buffer.
var arr = new BooleanArray( 2 );
// returns <BooleanArray>
var buf = arr.buffer;
// returns <ArrayBuffer>Size (in bytes) of the array.
var arr = new BooleanArray( 10 );
// returns <BooleanArray>
var nbytes = arr.byteLength;
// returns 10Offset (in bytes) of the array from the start of its underlying ArrayBuffer.
var ArrayBuffer = require( '@stdlib/array-buffer' );
var arr = new BooleanArray( 10 );
// returns <BooleanArray>
var offset = arr.byteOffset;
// returns 0
var buf = new ArrayBuffer( 240 );
arr = new BooleanArray( buf, 64 );
// returns <BooleanArray>
offset = arr.byteOffset;
// returns 64Size (in bytes) of each array element.
var arr = new BooleanArray( 10 );
// returns <BooleanArray>
var nbytes = arr.BYTES_PER_ELEMENT;
// returns 1Number of array elements.
var arr = new BooleanArray( 10 );
// returns <BooleanArray>
var len = arr.length;
// returns 10Creates a new boolean array from an array-like object or an iterable.
var arr = BooleanArray.from( [ true, false ] );
// returns <BooleanArray>
var len = arr.length;
// returns 2To invoke a function for each src value, provide a callback function.
function map( v ) {
return !v;
}
// Create a source array:
var src = [ true, false ];
// Create a new boolean array by inverting the source array:
var arr = BooleanArray.from( src, map );
// returns <BooleanArray>
var len = arr.length;
// returns 2
var v = arr.get( 0 );
// returns false
v = arr.get( 1 );
// returns trueA callback function is provided two arguments:
- value: source value.
- index: source index.
To set the callback execution context, provide a thisArg.
function map( v ) {
this.count += 1;
return !v;
}
// Create a source array:
var src = [ true, false ];
// Define an execution context:
var ctx = {
'count': 0
};
// Create a new boolean array by inverting the source array:
var arr = BooleanArray.from( src, map, ctx );
// returns <BooleanArray>
var len = arr.length;
// returns 2
var n = ctx.count;
// returns 2Creates a new boolean array from a variable number of arguments.
var arr = BooleanArray.of( true, false, false, true );
// returns <BooleanArray>
var len = arr.length;
// returns 4Returns the first element in an array for which a predicate function returns a truthy value.
function predicate( v ) {
return v === true;
}
var arr = new BooleanArray( 3 );
arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );
var v = arr.find( predicate );
// returns trueThe predicate function is provided three arguments:
- value: current array element.
- index: current array element index.
- arr: the array on which this method was called.
To set the function execution context, provide a thisArg.
function predicate( v ) {
this.count += 1;
return ( v === true );
}
var arr = new BooleanArray( 3 );
var context = {
'count': 0
};
arr.set( false, 0 );
arr.set( false, 1 );
arr.set( true, 2 );
var z = arr.find( predicate, context );
// returns true
var count = context.count;
// returns 3Returns the index of the first element in an array for which a predicate function returns a truthy value.
function predicate( v ) {
return v === true;
}
var arr = new BooleanArray( 3 );
arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );
var v = arr.findIndex( predicate );
// returns 0The predicate function is provided three arguments:
- value: current array element.
- index: current array element index.
- arr: the array on which this method was called.
To set the function execution context, provide a thisArg.
function predicate( v ) {
this.count += 1;
return ( v === true );
}
var arr = new BooleanArray( 3 );
var context = {
'count': 0
};
arr.set( false, 0 );
arr.set( false, 1 );
arr.set( true, 2 );
var z = arr.findIndex( predicate, context );
// returns 2
var count = context.count;
// returns 3Returns the last element in an array for which a predicate function returns a truthy value.
function predicate( v ) {
return v === true;
}
var arr = new BooleanArray( 3 );
arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );
var v = arr.findLast( predicate );
// returns trueThe predicate function is provided three arguments:
- value: current array element.
- index: current array element index.
- arr: the array on which this method was called.
To set the function execution context, provide a thisArg.
function predicate( v ) {
this.count += 1;
return ( v === true );
}
var arr = new BooleanArray( 3 );
var context = {
'count': 0
};
arr.set( true, 0 );
arr.set( false, 1 );
arr.set( false, 2 );
var z = arr.findLast( predicate, context );
// returns true
var count = context.count;
// returns 3Returns the index of the last element in an array for which a predicate function returns a truthy value.
function predicate( v ) {
return v === true;
}
var arr = new BooleanArray( 3 );
arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );
var v = arr.findLastIndex( predicate );
// returns 2The predicate function is provided three arguments:
- value: current array element.
- index: current array element index.
- arr: the array on which this method was called.
To set the function execution context, provide a thisArg.
function predicate( v ) {
this.count += 1;
return ( v === true );
}
var arr = new BooleanArray( 3 );
var context = {
'count': 0
};
arr.set( true, 0 );
arr.set( false, 1 );
arr.set( false, 2 );
var z = arr.findLastIndex( predicate, context );
// returns 0
var count = context.count;
// returns 3Returns an array element located at a nonnegative integer position (index) i.
var arr = new BooleanArray( 10 );
// Set the first element:
arr.set( true, 0 );
// Get the first element:
var v = arr.get( 0 );
// returns trueIf provided an out-of-bounds index, the method returns undefined.
var arr = new BooleanArray( 10 );
var v = arr.get( 100 );
// returns undefinedReturns a new array with each element being the result of a provided callback function.
function invert( v ) {
return !v;
}
var arr = new BooleanArray( 3 );
arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );
var out = arr.map( invert );
// returns <BooleanArray>
var z = out.get( 0 );
// returns false
z = out.get( 1 );
// returns true
z = out.get( 2 );
// returns falseThe callback function is provided three arguments:
- value: current array element.
- index: current array element index.
- arr: the array on which this method was called.
To set the function execution context, provide a thisArg.
function invert( v, i ) {
this.count += i;
return !v;
}
var arr = new BooleanArray( 3 );
var context = {
'count': 0
};
arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );
var out = arr.map( invert, context );
// returns <BooleanArray>
var count = context.count;
// returns 3;Reverses an array in-place.
var arr = new BooleanArray( 3 );
arr.set( true, 0 );
arr.set( false, 1 );
arr.set( false, 2 );
var out = arr.reverse();
// returns <BooleanArray>
var v = out.get( 0 );
// returns false
v = out.get( 1 );
// returns false
v = out.get( 2 );
// returns trueSets one or more array elements.
var arr = new BooleanArray( 10 );
// Get the first element:
var v = arr.get( 0 );
// returns false
// Set the first element:
arr.set( true );
// Get the first element:
v = arr.get( 0 );
// returns trueBy default, the method sets array elements starting at position (index) i = 0. To set elements starting elsewhere in the array, provide an index argument i.
var arr = new BooleanArray( 10 );
// Get the fifth element:
var v = arr.get( 4 );
// returns false
// Set the fifth element:
arr.set( true, 4 );
// Get the fifth element:
v = arr.get( 4 );
// returns trueIn addition to providing a single value, to set one or more array elements, provide an array-like object containing truthy and falsy values
var arr = new BooleanArray( 10 );
// Define an array of values:
var buf = [ '', 1, null ];
// Set the fifth, sixth, and seventh elements:
arr.set( buf, 4 );
// Get the sixth element:
var v = arr.get( 5 );
// returns trueA few notes:
- If
iis out-of-bounds, the method throws an error. - If a target array cannot accommodate all values (i.e., the length of source array plus
iexceeds the target array length), the method throws an error. - If provided a typed array which shares an
ArrayBufferwith the target array, the method will intelligently copy the source range to the destination range.
Sorts an array in-place.
function compare( a, b ) {
if ( a === false ) {
if ( b === false ) {
return 0;
}
return 1;
}
if ( b === true ) {
return 0;
}
return -1;
}
var arr = new BooleanArray( 3 );
arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );
arr.sort( compare );
var v = arr.get( 0 );
// returns true
v = arr.get( 1 );
// returns true
v = arr.get( 2 );
// returns falseThe compareFcn determines the order of the elements. The function is called with the following arguments:
- a: the first boolean value for comparison.
- b: the second boolean value for comparison.
The function should return a number where:
- a negative value indicates that
ashould come beforeb. - a positive value indicates that
ashould come afterb. - zero or
NaNindicates thataandbare considered equal.
Returns a new typed array containing the elements in reversed order.
var arr = new BooleanArray( 3 );
arr.set( true, 0 );
arr.set( false, 1 );
arr.set( false, 2 );
var out = arr.toReversed();
// returns <BooleanArray>
var v = out.get( 0 );
// returns false
v = out.get( 1 );
// returns false
v = out.get( 2 );
// returns true-
While a
BooleanArraystrives to maintain (but does not guarantee) consistency with typed arrays, significant deviations from ECMAScript-defined typed array behavior are as follows:- The constructor does not require the
newoperator. - Accessing array elements using bracket syntax (e.g.,
X[i]) is not supported. Instead, one must use the.get()method.
- The constructor does not require the
var Uint8Array = require( '@stdlib/array-uint8' );
var logEach = require( '@stdlib/console-log-each' );
var BooleanArray = require( '@stdlib/array-bool' );
// Create a boolean array by specifying a length:
var out = new BooleanArray( 3 );
logEach( '%s', out );
// Create a boolean array from an array of booleans:
var arr = [ true, false, true ];
out = new BooleanArray( arr );
logEach( '%s', out );
// Create a boolean array from an array buffer:
arr = new Uint8Array( [ 1, 0, 1, 1, 0, 1 ] );
out = new BooleanArray( arr.buffer );
logEach( '%s', out );
// Create a boolean array from an array buffer view:
arr = new Uint8Array( [ 1, 0, 1, 1, 0, 1 ] );
out = new BooleanArray( arr.buffer, 1, 2 );
logEach( '%s', out );
console.log( '%s', false );This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.
See LICENSE.
Copyright © 2016-2024. The Stdlib Authors.
