array code

Array.indexOf fix //JavaScript Function

Just an idiot fix to increase the number of my posts =b

//+ Jonas Raoni Soares Silva
//@ http://jsfromhell.com
[].indexOf || (Array.prototype.indexOf = function(v){
       for(var i = this.length; i-- && this[i] !== v;);
       return i;
});

example


var x = [0,1,2,3];

alert(x.indexOf(2));
alert(x.indexOf(4));

to javascript array jonas fix indexof jsfromhell raoni by jonasraoni on Aug 18, 2006 4 Comments

Array rotate //Javascript Function

Rotate the elements of an array with the minimum possible amount of movements.
It's thousands faster than using sequences of "array.unshift(array.pop())" or "array.push(array.shift())" due to memory moving on the "unshift" and "shift" methods. It also doesn't use a helper array, so it's fast and requires no aditional memory.

[UPDATED CODE CAN BE FOUND HERE]

//+ Jonas Raoni Soares Silva
//@ http://jsfromhell.com/array/rotate [v1.0]

rotate = function(a /*array*/, p /* integer, positive integer rotate to the right, negative to the left... */){ //v1.0
    for(var l = a.length, p = (Math.abs(p) >= l && (p %= l), p < 0 && (p += l), p), i, x; p; p = (Math.ceil(l / p) - 1) * p - l + (l = p))
        for(i = l; i > p; x = a[--i], a[i] = a[i - p], a[i - p] = x);
    return a;
};

Usage

document.write(
    "rotate([1,2,3], 2) = ", rotate([1,2,3], 2), "<br />",
    "rotate([1,2,3], -2) = ", rotate([1,2,3], -2), "<br />",
    "rotate([1,2,3], 1000) = ", rotate([1,2,3], 1000), "<br />"
)

to javascript array rotate jonas jsfromhell raoni by jonasraoni on Jun 15, 2006

getElementsAt //JavaScript Function

This function is able to get all the elements in a specific level of the array

example:

x = [-1, [[8, 22, -7], 32, [[4, 10, -2], 122]], 13];
alert(x.getElementsAt(3));

code:

//+ Jonas Raoni Soares Silva
//@ http://jsfromhell.com
Array.prototype.getElementsAt = function(level){
	var r = [], x = [], c = this, l = level, i;
	do
		if(i = c.length, !l)
			for(; i; r[r.length] = c[--i]);
		else
			for(; i; c[--i] instanceof Array && x.push(c[i], l - 1));
	while(l = x.pop(), (c = x.pop()) != undefined);
	return r;
}

to javascript array elements level jonas jsfromhell raoni by jonasraoni on Feb 14, 2006

Array Shuffle //JavaScript Function

[UPDATED CODE AND HELP CAN BE FOUND HERE]

usage

alert(shuffle([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]));

code based on Fisher-Yates (never heard about him hahaha) algorithm

//+ Jonas Raoni Soares Silva
//@ http://jsfromhell.com/array/shuffle [v1.0]

shuffle = function(o){ //v1.0
	for(var j, x, i = o.length; i; j = parseInt(Math.random() * i), x = o[--i], o[i] = o[j], o[j] = x);
	return o;
};

to javascript array shuffle randomize jonas jsfromhell raoni by jonasraoni on Nov 03, 2005

Arrange //JavaScript Function

It arranges elements in an array, the "n" parameter determines the amount of elements in each combination and the "m" one is a boolean which says if the function should return an array with an "index map" or real values.

[UPDATED CODE AND HELP CAN BE FOUND HERE]

//+ Jonas Raoni Soares Silva
//@ http://jsfromhell.com/array/arrange [v1.0]

arrange = function( v, n, m ){
 	for( var i, j, k, sep = sep || "", l = v.length, r = new Array( i = Math.pow( l, n ) ), c = ( new Array( n + 1 ) ).join( 0 ).split( "" ); i; )
		for( r[--i] = new Array( j = n ), k = 1; j--; r[i][j] = m ? c[j] : v[c[j]], k && ( ++c[j] != l && --k, c[j] %= l ) );
	return r;
};

Example

document.write( arrange( ["A", "B", "C" ], 3, 1 ).join( "<br />" ), "<hr />" );
document.write( arrange( ["A", "B", "C" ], 3, 0 ).join( "<br />" ) );

to javascript array math arrange combinatory jonas jsfromhell raoni by jonasraoni on Sep 09, 2005

Permute //JavaScript Function

It permutes elements in an array, the "m" parameter is a boolean which determines if the function should return an array with an "index map" or the real value.

[UPDATED CODE AND HELP CAN BE FOUND HERE]

//+ Jonas Raoni Soares Silva
//@ http://jsfromhell.com/array/permute [v1.0]

permute = function( v, m ){
	for( var j, l = v.length, i = ( 1 << l ) - 1, r = new Array( i ); i; )
		for( r[--i] = [], j = l; j; i + 1 & 1 << --j && ( r[i].push( m ? j : v[j] ) ) );
	return r;
};

Example

document.write( permute( ["A", "B", "C" ], 1 ).join( "<br />" ), "<hr />" );
document.write( permute( ["A", "B", "C" ], 0 ).join( "<br />" ) );

to javascript array math permute combinatory jonas jsfromhell raoni by jonasraoni on Sep 09, 2005

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