shuffle two arrays in same order in javascript

Question

I have two arrays
var skladby=["skladba00", "skladba01", "skladba02", "skladba03"];
var zoznam=["text00", "text01", "text02", "text03"];

I would like to randomize/shuffle this two arrays in same order but items in arrays on [0] position must stay on their positions.
i.e.
var skladby=["skladba00", "skladba02", "skladba03", "skladba01"];
var zoznam=["text00", "text02", "text03", "text01"];

thx for your answers.

Can we assume the missing quotes on the strings are a typo/paste issue? — Mark Schultheiss, May 02 '13 at 12:32

kennebec · Accepted Answer · 2013-05-02T14:03:40.297

To change your arrays in place, get the shuffled order first and add the new arrangements to the end of the existing arrays.

Then splice out from index 1 to where the new arrangement begins (the original length).

The elements at index 0 are not affected.

var skladby= ["skladba00", "skladba01", "skladba02", "skladba03"];
var zoznam= ["text00", "text01", "text02", "text03"];

var i=0, len= skladby.length, next, order=[];
while(i<len)order[i]= ++i; //[1,2,3...]
order.sort(function(){return Math.random()-.5});


for(i= 0; i<len; i++){
    next= order[i];
    skladby.push(skladby[next]);
    zoznam.push(zoznam[next]);
}
skladby.splice(1, len);
zoznam.splice(1, len);

/* returned values

skladba00,skladba03,skladba01,skladba02

text00,text03,text01,text02 */

Dineshkani · Answer 2 · 2013-05-02T12:47:38.150

Shuffle a One array With Index and then Use that array reorder these two arrays

var skladby=["skladba00", "skladba02", "skladba03", "skladba01"];
var zoznam=["text00", "text02", "text03", "text01"];
var arrayShuff = new Array();
for (var i=0;i< skladby.length;i++){
arrayShuff.push(i);
}

fisherYates(arrayShuff);
function fisherYates ( myArray ) {
   var i = myArray.length, j, tempi, tempj;
   if ( i === 0 ) return false;
   while ( --i ) {
     j = Math.floor( Math.random() * ( i + 1 ) );
     tempi = myArray[i];
     tempj = myArray[j];
     myArray[i] = tempj;
     myArray[j] = tempi;
   }
}
var temp_skladby = new Array();
for (i=0;i < arrayShuff.length;i++){
   temp_skladby.push(skladby[arrayShuff[i]]);
}
skladby = new Array();
skladby = temp_skladby.slice(0);
temp_skladby = new Array();
for (i=0;i < arrayShuff.length;i++){
   temp_skladby.push(zoznam[arrayShuff[i]]);
}
zoznam = new Array();
zoznam = temp_skladby.slice(0);
console.log(zoznam);
console.log(skladby);

See Demo

That fisherYates methods are refer from http://sedition.com/perl/javascript-fy.html — Dineshkani, May 02 '13 at 12:42

score 1 · Answer 3 · answered May 02 '13 at 13:19

Find random numbers first and then make the same swaps in both of the arrays:

        var skladby = ["skladba00", "skladba01", "skladba02", "skladba03", "skladba04", "skladba05"];
        var zoznam = ["text00", "text01", "text02", "text03", "text04", "text05"];

        if (skladby.length == zoznam.length) {
            var arr = [];
            var length = skladby.length;
            while (arr.length < length-1) {
                var randomnumber = Math.ceil(Math.random() * (length - 1));
                var found = false;
                for (var i = 0; i < arr.length; i++) {
                    if (arr[i] == randomnumber) {
                        found = true;
                        break;
                    }
                }
                if (!found)
                    arr[arr.length] = randomnumber;
            }

            var swapTemp;
            for (var i = 1; i < length; i++) {
                swapTemp = skladby[i];
                skladby[i] = skladby[arr[i - 1]];
                skladby[arr[i - 1]] = swapTemp;

                swapTemp = zoznam[i];
                zoznam[i] = zoznam[arr[i - 1]];
                zoznam[arr[i - 1]] = swapTemp;
            }
        }

score 0 · Answer 4 · edited May 23 '17 at 12:18

function shuffle(o){ 
    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;
};

var skladby=["skladba00", "skladba02", "skladba03", "skladba01"];
var zoznam=["text00", "text01", "text02", "text03"];

// concat the first element with the shuffeld other elements
var skladbySorted = skladby.slice(0,1).concat(shuffle(skladby.slice(1,skladby.length)));
var zoznamSorted = zoznam.slice(0,1).concat(shuffle(skladby.slice(1,zoznam.length)));

console.log(skladbySorted);
console.log(zoznamSorted);

This would work for all sizes of your input array, not only 4 elements

credit to shuffle method goes to Jeff

shuffle two arrays in same order in javascript

4 Answers4