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Shuffle
Shuffle elements of an array-like object.
Installation
npm install @stdlib/random-shuffle
Usage
var shuffle = require( '@stdlib/random-shuffle' );
shuffle( arr[, options] )
Shuffles elements of an array-like object.
var arr = [ 1, 2, 3 ];
var out = shuffle( arr );
// e.g., returns [ 3, 1, 2 ]
The function accepts the following options
:
-
copy:
string
indicating whether to return a copy (deep
,shallow
ornone
). Default:shallow
.
By default, the function returns a shallow copy. To mutate the input array
(e.g., when input values can be discarded or when optimizing memory usage), set copy
to none
.
var arr = [ 1, 2, 3 ];
var out = shuffle( arr, {
'copy': 'none'
});
var bool = ( arr === out );
// returns true
To return a deep copy, set the copy
option to deep
.
var obj = {
'beep': 'boop'
};
var arr = [ [ obj ], [ obj ], [ obj ] ];
// Deep copy:
var out = shuffle( arr, {
'copy': 'deep'
});
var bool = ( arr === out );
// returns false
bool = ( arr[2] === out[2] );
// returns false
// Shallow copy:
out = shuffle( arr, {
'copy': 'shallow'
});
bool = ( arr === out );
// returns false
bool = ( arr[2] === out[2] );
// returns true
shuffle.factory( [options] )
Returns a function
to shuffle elements of array
-like objects.
var myshuffle = shuffle.factory();
The function accepts the following options
:
-
copy:
string
specifying the default copy option (deep
,shallow
ornone
). Default:shallow
. - seed: pseudorandom number generator seed.
To seed the underlying pseudorandom number generator, set the seed
option.
var myshuffle = shuffle.factory({
'seed': 239
});
var out = myshuffle( [ 0, 1, 2, 3, 4 ] );
// e.g., returns [ 3, 4, 1, 0, 2 ]
By default, the returned functions create shallow copies when shuffling. To override the default copy
strategy, set the copy
option.
var myshuffle = shuffle.factory({
'copy': 'none',
'seed': 867
});
// Created shuffle function mutates input array by default:
var arr = [ 1, 2, 3, 4, 5, 6 ];
var out = myshuffle( arr );
var bool = ( arr === out );
// returns true
// Default option can be overridden:
arr = [ 1, 2, 3, 4 ];
out = myshuffle( arr, {
'copy': 'shallow'
});
bool = ( arr === out );
// returns false
Examples
var shuffle = require( '@stdlib/random-shuffle' );
var result;
var data;
var i;
data = new Array( 20 );
for ( i = 0; i < data.length; i++ ) {
data[ i ] = i;
}
for ( i = 0; i < 10; i++ ) {
result = shuffle( data );
console.log( result );
}
See Also
-
@stdlib/random-sample
: sample elements from an array-like object.
Notice
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.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.