2 dimensional array sum in javascript

Question

I need to add recurrently a 2 dimensional array. The ideea is that I have a generated 2 dimensional array and I have to get the sum of all the generated arrays. I tried writing:

sum+=parseFloat(twoArray[a][b]);

however the script is blocked and I do not get anything. it is a loop so the values of a, b float from 0 to a variable inserted by the user. I have tested the script and this is the line where it breaks.

if (k>=3){                          
    for(var i=0;i<A.length;i++){
        var smaller=new Array(A.length-1);
        for(var h=0;h<smaller.length;h++){
            smaller[h]=new Array(smaller.length);
        }
        for(var a=1;a<A.length;a++){
            for(var b=0;b<A.length;b++){
                if(b<i){
                    smaller[a-1][b]=A[a][b];
                }
                else if(b>i){
                    smaller[a-1][b-1]=A[a][b];
                }
            }   
        }
        sum+=parseFloat(smaller[a][b]);
        alert (sum);
        //dam valorile
    }
}
}

Can you add the other part of the script with an example input — Manse
– Manse, Commented May 21, 2012 at 16:28
it's a very long script. the ideea is that i have a 2 dimensional array A of k lines of k columns and I generated an array one line and one column smaller. I want to add all the resulted arrays in a sum of k-1 lines and k-1 columns. — viktor
– viktor, Commented May 21, 2012 at 16:32
obviously (after re-indentation) your array smaller has no item at [a][b], as it's length is only a-1. Could you please post the error you get when "the script breaks"? — Bergi
– Bergi, Commented May 21, 2012 at 16:49
the errors are at: smaller[h]=new Array(smaller.length); and sum+=parseFloat(twoArray[a][b]); — viktor
– viktor, Commented May 21, 2012 at 17:00

Denys Séguret · Accepted Answer · 2012-05-21 16:30:58Z

1

Put a

try {
  sum+=parseFloat(twoArray[a][b]);
} catch (e) {
   console.log(e)
}

in your loop.

So you'll see where it gets blocked and invalid inputs won't prevent the remaining summations.

Of course, I suppose you correctly checked array indexes vs lengths before.

answered May 21, 2012 at 16:30

Denys Séguret

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4 Comments

viktor Over a year ago

I have added the loop code. I have checked the generated arrays with alert and it all works fine, however it's the sum that's generating the problem.

Denys Séguret Over a year ago

Did you try what I suggest to check there is no exception ?

viktor Over a year ago

i have already checked the generated arrays and they are as they are supposed to be. the problem should be in the syntax at smaller[a][b]; if I use only smaller it works, but it takes only the first value of all the arrays.

viktor Over a year ago

I have tried to check and there are 2 breakpoints at: smaller[h]=new Array(smaller.length); and sum+=parseFloat(twoArray[a][b]);

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