How do I loop through chars in a string in javascript?

Question

I have the following js and receiving error at the foreach loop:

function bitCount(n) {
var strBitCount = (n >>> 0).toString(2);
var answer = 0;
var c = '';

foreach(c in strBitCount)
{
    if(Number(c) == 1)
    {
        answer++;
    }
}
  return answer;
}

forEach is an array method: arr.forEach(function (el) {...} — Andy
– Andy, Commented Mar 27, 2016 at 19:40

Matías Fidemraizer · Accepted Answer · 2016-03-27 19:44:12Z

16

JavaScript has no foreach block as other languages.

What you can do is using Array.prototype.forEach:

Array.from("hello").forEach(function(character) {
  console.log(character);
});

Well, and in ES2015 and above, you can use for..of

for (let character of "hello") {
  console.log(character);
}

answered Mar 27, 2016 at 19:44

Matías Fidemraizer

65.1k19 gold badges132 silver badges216 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

J.S.Orris Over a year ago

I accidentally hit the downvote I think....mad it an upvote...thanks for your answer.

Matías Fidemraizer Over a year ago

@JeffOrris No problem. I've checked you found more useful other answer. BTW I still think that now you know that foreach doesn't syntactically exist in JavaScript.

Pointy · Accepted Answer · 2016-03-27 19:43:12Z

2

You can use an ordinary for loop and index into the string with []:

for (var i = 0; i < strBitCount.length; ++i)
  if (Number(strBitCount[i]) === 1)
    answer++;

Note that you could also just add the digit to answer:

for (var i = 0; i < strBitCount.length; ++i)
  answer += Number(strBitCount[i]); // or +strBitCount[i]

answered Mar 27, 2016 at 19:43

Pointy

415k62 gold badges600 silver badges631 bronze badges

Comments

Andy · Accepted Answer · 2016-03-27 19:59:48Z

1

You can filter on those characters in the string that match your test and return the length of that array.

function bitCount(n) {
  var strBitCount = (n >>> 0).toString(2);
  var equalsOne = function (char) { return +char === 1; }
  return [].filter.call(strBitCount, equalsOne).length;
}

DEMO

edited Mar 27, 2016 at 19:59

answered Mar 27, 2016 at 19:53

Andy

63.6k13 gold badges72 silver badges99 bronze badges

1 Comment

J.S.Orris Over a year ago

Very nice sir! and elegant.

Collectives™ on Stack Overflow

How do I loop through chars in a string in javascript?

3 Answers 3

2 Comments

Comments

1 Comment

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

1 Comment

Related