How to push a boolean into an array? "undefined" error

Question

Why does the console print "undefined" when I print index 3? I'm trying to set index 3 to false and after 7 secs set it to true.

I've tried to change "nr", index 2, with success trying to narrow down the problem.

if (Math.random() < 0.005) {
    nx = Math.random()*1000; //index0
    ny = 200; //index1
    nr = 5;//index2
    var nfall = false; //index3
    Apples.push([nx,ny,nr,nfall]); //simply inserting 'false' into index 3 doesn't work either.

    setTimeout(function(){ Apples[2][2] = 500; Apples[2][3] = true;}, 7000); //3rd apple

    console.log("New circle, x:"+Apples[2][0]+" y:"+Apples[2][1]+" nr:"+Apples[2][2] +" nfall:"+Apples[2[3]]);
//What works - in 7 seconds "nr" is updated from 5 to 500, but nfall is still undefined and NOT = true

Initially I expect the output of false from index 3 "nfall" then I expect the output of true from index 3 "nfall" after 7 secs.

Thank you

console.log("New circle, x:"+Apples[2][0]+" y:"+Apples[2][1]+" nr:"+Apples[2][2] +" nfall:"+Apples[2][3]); plz change in Apples[2[3]] to Apples[2][3] — channasmcs
– channasmcs, Commented Apr 17, 2019 at 3:20

Sidney · Accepted Answer · 2019-04-17 03:14:26Z

1

In your console.log call, you're accessing the array like this:

Apples[2[3]]

But it should be

Apples[2][3]

In the first version, you're accessing index 3 of the number 2 which actually is not an error, just undefined.

answered Apr 17, 2019 at 3:14

Sidney

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Comments

Jack Bashford · Accepted Answer · 2019-04-17 03:23:36Z

0

Your issue is the last part - you're accessing Apples[2[3]] which doesn't exist, and it's invalid syntax. You want to get the third item in Apples (which is an array), then access the fourth item of that array - do it simply with `Apples[2][3]:

const Apples = [1, 2, [3, 4, 5, 6]];
console.log(Apples[2][3]);

answered Apr 17, 2019 at 3:23

Jack Bashford

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