Answers for "delete a specific number from array in optimize way"

array remove element js

var colors = ["red","blue","car","green"];
var carIndex = colors.indexOf("car");//get  "car" index
//remove car from the colors array
colors.splice(carIndex, 1); // colors = ["red","blue","green"]

js delete all from array

var list = [1, 2, 3, 4];
function empty() {
    //empty your array
    list.length = 0;
}
empty();