Write an algorithm that takes an array and moves all of the zeros to the end

Question

Write an algorithm that takes an array and moves all of the zeros to the end, preserving the order of the other elements.

For example:

moveZeros([false,1,0,1,2,0,1,3,"a"]) // returns[false,1,1,2,1,3,"a",0,0]

My code:

var moveZeros = function (arr) {

var zeros = []; 
var others = [];
var res;

var arrayLength = arr.length;
for (var i = 0; i < arrayLength; i++) {
if   (arr[i] ==  0) {
 zeros.push(arr[i]);
 } else {
      others.push(arr[i]);
 }
}
var res = others.concat( zeros );

return res;


}

I get the following result:

Expected:    ["a","b",null,"c","d",1,false,1,3,[],1,9,{},9,0,0,0,0,0,0,0,0,0,0],
Instead got: ["a","b",null,"c","d",1,1,3,1,9,{},9,0,0,0,false,0,0,[],0,0,0,0,0]

The expected result is quite close to what I achieved (see above) . I don't understand why I have false in a different place?

Answer 1

try this simply

var arr = [false,1,0,1,2,0,1,3,"a"];
arr.sort(function(a,b){if (a===0){return 1}});
document.body.innerHTML += JSON.stringify(arr);

Answer 2

Try to use a normal for loop and splice at this context to make your job done,

var arr = [false,1,0,1,2,0,1,3,"a"];
for(var i=arr.length;i>0;i--){
  if(arr[i] === 0){  arr.push(arr.splice(i,1).pop()); }
}
console.log(arr); //[false, 1, 1, 2, 1, 3, "a", 0, 0]
document.body.innerHTML += JSON.stringify(arr);

Answer 3

Use Array#splice() and Array#push().

function moveZeros(a) {
    var i = a.length - 1;
    while (i--) {
        if (a[i] === 0) {
            a.push(a.splice(i, 1)[0]);
        }
    }
    return a;
};

var array = [false, 1, 0, 1, 2, 0, 1, 3, "a"];
document.write('<pre>' + JSON.stringify(moveZeros(array), 0, 4) + '</pre>');

Another approach with swapping items.

function moveZeros(array) {
    var length = array.length,
        i = length;

    while (--i) {
        if (array[i] !== 0) continue;
        length--;
        while (i < length) {
            [array[i + 1], array[i]] = [array[i], array[i + 1]];
            i++;
        }
    }
    return array;
}

var array = [false, 1, 0, 1, 2, 0, 1, 3, "a"];

console.log(...moveZeros(array));

Answer 4

The code snippet below should work , please try , reason for null is that the length of the arr starts count from zero so when using <= you should subtract 1 from the total length.

var moveZeros = function (arr) {
  // TODO: Program me
  let zero = []
  let others = []
  let together = []
  
    for (let i =0; i <= arr.length-1; i++){
      if (arr[i] === 0){
        zero.push(arr[i])
        }
      else{ 
        others.push(arr[i])
      }
    }
  together = others.concat(zero)
  return together
}

Answer 5

var titleCase = function(title) {
var arr = [];
for (i = 0; i < title.length ; i++) {
    if (title[i] !== 0 ) {
        arr.push(title[i]);
    }
}
for (i = 0 ; i < title.length ; i++) {
    if (title[i] == 0 ) {
        arr.push(title[i]);
    }
}
return  arr;
}

Answer 6

You could use the filter() method to achieve your goal. With the arrow notation you can shorten the code. For example: arr => arr === 0 is the shorthand for the anonymous filter function function(arr) { return arr === 0; }

var moveZeros = function (arr) {
    const zeros = arr.filter (arr => arr === 0);
    const others = arr.filter (arr => arr !== 0);
    return others.concat(zeros);
}

Answer 7

var arr = [false,1,0,1,2,0,1,3,"a"]
function moveZeros(arr){
var zeros = [];
var others = [];
var output;
for (var i=0; i< arr.length; i++){
if (arr[i]===0){
zeros.push(arr[i]);
}else{
others.push(arr[i])
}
}

output = others.concat(zeros);
console.log(output);
}

moveZeros([false,1,0,1,2,0,1,3,"a"]);