JavaScript 2D array setting value to wrong coordinations

Question

I'm trying to make 2D field:

var field=[];
    N = 8;
    M = 12;

for (Y=0;Y<M;Y++){

  for (X=0;X<N;X++){
    field[X,Y]=0;      //trying to make 2d field with coordinates X,Y
  }; 
};

function functiontest(){
  field[3,10]=1;      //trying to set to coordinates "3,10" value 1
  alert(field[2,10]);   //ALERTS 1 for some reason
};

I'm trying to set value 1 to coordinates "3, 10" ,but it sets value 1 to all coordinates, which have second coordinates (X,10). When I add script, that sets blue background to DIV with value 1 (id is same as coordinates), it sets it for the whole line.

function functionblue(){
  for (Y=0;Y<M;Y++){
    for (X=0;X<N;Z++){
      if (field[X,Y]==0){
        $("#z"+X+""+Y).css("background","blue");     //Divs and its IDs work properly
      }; 
    };
  };
};

Image Link.

so how do I set value just toto one point (not line)?

Change field[X,Y] to field[X][Y].

thefourtheye
– thefourtheye

2015-01-17 14:37:22 +00:00
Commented Jan 17, 2015 at 14:37 — thefourtheye
– thefourtheye, Commented Jan 17, 2015 at 14:37

Bhargav Rao · Accepted Answer · 2015-03-05 04:38:02Z

2

Try this for a 8 × 10 field

n= 8;
m= 12;
var field1= new Array(n);

for (Y=0;Y<n;Y++){
  var field2= new Array(m);
  for (X=0;X<m;X++){
    field2[X]=0;
  }; 
  field1[Y]= field2;
};

function functiontest(){
  field1[3][10]=1;     
  alert(field1[2][10]);
};

edited Mar 5, 2015 at 4:38

Bhargav Rao

52.6k29 gold badges130 silver badges142 bronze badges

answered Jan 17, 2015 at 14:56

Anirudh K

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1 Comment

Pruzo Over a year ago

This was a very helpfull answer, functionblue() with the change @thefourtheye mentioned works properly now. Thank you!

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