Home / Questions / 161158
Accepted
UnexpectedCharacter
Asked: 2020-05-04 01:03:10 +0800 CST 2020-05-04 01:03:10 +0800 CST

Create a new array in for JS loop

  • 772

I am trying to create a new array for each return of a for.

var route = [];

for (var i = 0; i < 5; i++) {
  route[i].push(result.routes[0].overview_path[i].lat());
  route[i].push(result.routes[0].overview_path[i].lng());

  console.log(route[i]);

}

But the console tells me that it isundefined

javascript

2 Answers

  1. Best Answer

    You can't push to an undefined:

    var route = []; //array vacío

for (var i = 0, i < 5; i++) {
  //estás asumiendo que route[i] tiene un array
  //pero...
  console.log(route[i]); //undefined
  //fallaría
  //route[i].push(result.routes[0].overview_path[i].lat());
  //route[i].push(result.routes[0].overview_path[i].lng());

  //solución:
  let aux=[];
  aux.push(result.routes[0].overview_path[i].lat());
  aux.push(result.routes[0].overview_path[i].lng());
  route.push(aux);
}
    • 3

  2. You are trying to access position i of an array that is not initialized. Initializing it solves the problem.

    var route = [0];

for (var i = 0, i < 5; i++) {
                        route[i].push(result.routes[0].overview_path[i].lat());
                        route[i].push(result.routes[0].overview_path[i].lng());

console.log(route[i]);

                    }
    • 0