无法读取未定义的属性“长度”。”

Question

This program should print out the arrays.

But why am I getting

Cannot read property 'length' of undefined.

I am new to learning JavaScript. Thank you.

 const animearray= [ ["mursalin",'tuly','ahad'], ['eren','luffy','minato'], ['asif','sara','rakib'] ] for (let i=0;i<=animearray.length;i++){ const rows = animearray[i]; for (let j=0;j<=rows.length; j++){ console.log(rows[j]); } }

Answer 1

for (let i=0;i<=animearray.length;i++)

Since arrays are indexed from 0 to length-1 , where length is the number of elements in the array, the program is throwing an error when i equals the array length. Iterating upto animearray.length-1 would solve the problem.

Answer 2

 const animearray = [ ["mursalin", 'tuly', 'ahad'], ['eren', 'luffy', 'minato'], ['asif', 'sara', 'rakib'] ] animearray.forEach(function(e) { e.forEach(function(a) { console.log(a); }); });

for (let i = 0; i < animearray.length; i++) {
  const rows = animearray[i];
  for (let j = 0; j < rows.length; j++) {
    console.log(rows[j]);
  }
}

but if you want to loop through array or multidimensional array then you can use forEach loop also

    animearray.forEach(function (e) {
      e.forEach(function (a) {
        console.log(a);
      });
    });

Answer 3

You are iterating for an extra element you have initialized the I=0 and loop is running 4 times which means checking 0,1,2,3 where on 3rd iteration it is not finding anything

 const animearray= [ ["mursalin",'tuly','ahad'], ['eren','luffy','minato'], ['asif','sara','rakib'], ] for (let i=0;i<=animearray.length-1;i++){ const rows = animearray[i]; for (let j=0;j<=rows.length-1; j++){ console.log(rows[j]); } }