practice_8

let empty_object = {};
let obj = {x: 10, y: 10.5};

console.log(obj); // {x: 10, y: 10.5 }
console.log(obj.x); // 10
console.log(obj.y); // 10.5

obj.x = -1;
obj.z = 100;
delete obj.y;

for(let key in obj) {
  console.log(key, obj[key]);
}
// "x" -1
// "z" 100


let my_key = 'x';
console.log(obj[my_key]); // -1;

my_key = 'z';
console.log(obj[my_key]); // 100;