How to rearrange array in place using loop

user_2181397 0
Viewed 118

I have this array [-1, 8, -1, 6, -1, 4, -1, 2, 0, -1]

I want to rearrange in place using the loop, where the element will place in its index

For example, element 8 will be placed in the 8th index, element 0 will be in the 0th index

output [0,-1,2,-1,4,-1,6,-1,8,-1];

This is my code

let arr = [-1, 8, -1, 6, -1, 4, -1, 2, 0, -1];

for (let i = 0; i < arr.length; i++) {
  const elem = arr[i];
  // console.log('---',elem)
  if (i !== arr[i]) {
    if (arr[i] !== -1) {

      const valInd = arr[arr[i]];
      arr[arr[i]] = elem;
      arr[i] = valInd
    }
  }

};

console.log(arr);

Please help me understand where I am missing

sorting javascript
3 Answers

You forgot to sort an array. First sort it and then use your logic

let arr = [-1, 8, -1, 6, -1, 4, -1, 2, 0, -1];
arr.sort()
for (let i = 0; i < arr.length; i++) {
  const elem = arr[i];
  // console.log('---',elem)
  if (i !== arr[i]) {
    if (arr[i] !== -1) {

      const valInd = arr[arr[i]];
      arr[arr[i]] = elem;
      arr[i] = valInd
    }
  }

};

console.log(arr);

user_169246320 

let arr = [-1, 8, -1, 6, -1, 4, -1, 2, 0, -1];
let output = new Array(arr.length).fill(-1);

arr.forEach(el => {
  if(el === -1) return;
  output[el]= el;
});
console.log(output);

user_84370990

I think this code will help you, if you want only run for this items.

let arr = [-1, 8, -1, 6, -1, 4, -1, 2, 0, -1];
for (let i = 0; i < arr.length; i++) {
  if (arr.includes(i)) {
    const ind = arr.indexOf(i);
    arr[ind] = arr[i];
    arr[i] = i;
  }
}
console.log(arr);

user_78657590
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