Question

I have the following 2D array

var items = [['al','bv','sd'],
             ['al','cc','ab'],
             ['cv','vv','sw'],
             ['al','bv','sd']
            ];

I need a function which will return me a similar array but with distinct values. For example, in the above array, ['al','bv','sd'] happens twice.

I would like the function to return me:

var items = [['al','bv','sd'],
             ['al','cc','ab'],
             ['cv','vv','sw']
            ];

Answer 1

You have to loop two (or three times):

1. Loop through all “rows”, from beginning to the end

2. Loop again, through all “rows”, from beginning to the end

   • If the lists are equal, ignore it
   • Otherwise,

3. Loop through all “columns”:

   • If the values are not equal, jump to the parent loop.
   • After the loop, remove the element using the .splice method.

Demo: http://jsfiddle.net/EuEHc/

Code:

for (var i=0; i<items.length; i++) {
    var listI = items[i];
    loopJ: for (var j=0; j<items.length; j++) {
        var listJ = items[j];
        if (listI === listJ) continue; //Ignore itself
        for (var k=listJ.length; k>=0; k--) {
            if (listJ[k] !== listI[k]) continue loopJ;
        }
        // At this point, their values are equal.
        items.splice(j, 1);
    }
}