Invert an array of booleans in JavaScript - Stack Overflow

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I am trying to invert the values of a string of boolean values so that instead of

inverted([true, false, true, false, true])

it is [false, true, false, true, false]

So far I have e up with this:

function inverted(bools) {
    var inversion = [];
    var string= [];
    while(!bools) {
      string.push(bools);
    }
    return inversion;
}

But my code is not working, any and all help will be much appreciated!

I am trying to invert the values of a string of boolean values so that instead of

inverted([true, false, true, false, true])

it is [false, true, false, true, false]

So far I have e up with this:

function inverted(bools) {
    var inversion = [];
    var string= [];
    while(!bools) {
      string.push(bools);
    }
    return inversion;
}

But my code is not working, any and all help will be much appreciated!

• javascript
• arrays
• boolean

Share Improve this question Follow edited Mar 31, 2017 at 2:11 gyre 16.8k44 gold badges4040 silver badges4747 bronze badges asked Mar 31, 2017 at 1:21 lois vlois v 2111 silver badge77 bronze badges 1

• 1 to be frank there are obvious issues in your code - you update string variable but return inversion array in the end. Also you assume and iterate with a truthy condition. You need to iterate on the array and push an inversion on the boolean. – moha297 Commented Mar 31, 2017 at 1:31

Add a ment  | 

8 Answers 8

Sorted by: Reset to default 6

You can use .map(), ! operator to invert Boolean value, return array of results

function inverted(bools) {
   return bools.map(function(bool) {return !bool})
}

function inverted(bools) {
  for(var i = 0; i < bools.length; i++) {
     bools[i] = !bools[i];
   }
  return bools;
}

Use it as

var bools = [true, false, true];
bools = inverted(bools);

Your code is just one big mistake. You do not understand basic principles of working with arrays. Do not just use my solution, please read some articles about iterating and getting an element from an array. This one should work:

function inverted(bools) {
  var i, _i, inversion = [];

  for(i = 0, _i = bools.length; i < _i; i++){
    inversion[i] = !bools[i];
  }
  return inversion;
}

You can do it like this:

• Convert the string to a JavaScript array using JSON.parse().
• Invert all the booleans using Array.prototype.map();
• Convert back to a string using JSON.stringify().

const booleans = "[true, false, true, false, true]";
const inverted = JSON.stringify(JSON.parse(booleans).map(b => !b));

console.log(inverted);

If by a "string", you actually mean an array, you don't need to convert to/from a string and can just do:

const booleans = [true, false, true, false, true];
const inverted = booleans.map(b => !b);

Though many answers here are already great, I thought I would chip in my "golfed" regex solution:

function inverted (b) {
 return b.map(/f/.test, /f/)
}

console.log(
  inverted([true, false, true, false])
)

You need to split up bools with bools.split(). Then you can check and invert them. You also are not putting anything in inversion[] prior to returning it. Something like the below should work:

function inverted(bools) {
var inversion = [];
var string= bools.split(",");
for(var i=0; i<string.length(); i++) {
  inversion.push(string[i]);
}

return inversion;

}

This is another way to achieve that :

var booleans = [true, false, true, false, true];

function inverted(bools) {
    var inversion = [],i=0;

    while(i< bools.length) {
      inversion.push(!(bools[i]));
      i++;
    }
    return inversion;
}

var inverted =  inverted(booleans);

console.log(inverted);//Outpu : [false, true, false, true, false]

let myArray = [true, false, false, true]
// single line solution:
let invertedArray = myArray.map((bool) => !bool)

console.log(invertedArray)

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