CODEWITHSUNDEEP
javascriptarraysloopsfor-loop
Pat8
Pat8

Reputation: 1036

How do I return the number of elements in an array using for of loop javascript?

How do I return the number of elements in an array using for of loop javascript?

I know how I can use a for loop to do this but I was wondering if there is a way to do this with a for of loop. In this case would using a regular for loop be better and or the only way to do this is with a loop?

Regular for loop that prints the number of elements in the array:

const arr = [1, 2, 3, 4];

function logElementForLoop(arr) {
  console.log("For Loop");
  let elemInArr = 0;
  for (let i = 0; i < arr.length; i++) {

    elemInArr = i + 1;
  }
  console.log(elemInArr);
}

logElementForLoop(arr);

Upvotes: 0

Views: 180

Answers (5)

Sven.hig
Sven.hig

Reputation: 4519

Using a for of loop

const arr = [1, 2, 3, 4];

function logElementForLoop(arr) {
  console.log("For Loop");
  let elemInArr = 0;
  for (let i of arr ) {

    elemInArr = arr.indexOf(i) + 1;
  }
  console.log(elemInArr);
}

logElementForLoop(arr);

or simply increment elemInArr

const arr = [1, 2, 3, 4];

    function logElementForLoop(arr) {
      console.log("For Loop");
      let elemInArr = 0;
      for (let i of arr ) {

        elemInArr++
      }
      console.log(elemInArr);
    }
logElementForLoop(arr)

Upvotes: 1

Simone Sanfratello
Simone Sanfratello

Reputation: 1610

I guess you are looking for something like for of or for in loops

let count = 0
for(const item of array) {
  count ++
}
console.log('array contains', count, 'elements')

or

let count = 0
for(const index in array) {
  count ++
}
console.log('array contains', count, 'elements')

Upvotes: 2

tarkh
tarkh

Reputation: 2549

Well, if you need to count array elements in for loop..? then

const arr = [1, 2, 3, 4, 5];

// Counter var
let counter = 0;

// Count in for loop
for(let i = 0; i < arr.length; i++) counter++;

// Log
console.log(counter);

Upvotes: 1

Mamun
Mamun

Reputation: 68933

I was wondering if there is a way to do this with a for of loop...

Yes, it is possible, simply increment the variable (elemInArr) inside the loop:

const arr = [1, 2, 3, 4];

function logElementForLoop(arr) {
  console.log("For Loop");
  let elemInArr = 0;
  for (let i of arr) {
    elemInArr++;
  }
  console.log(elemInArr);
}

logElementForLoop(arr);

Upvotes: 3

Nina Scholz
Nina Scholz

Reputation: 386746

You need to add 1 to the count, instead of assigning the index plus one.

function logElementForLoop(arr) {
    console.log("For Loop");
    let elemInArr = 0;
    for (let i = 0; i < arr.length; i++) {
        // add one for each element
        // elemInArr = elemInArr + 1;  // is doing it the long way
        // elemInArr += 1;             // jsut add one, handy for adding different values than one
        elemInArr++;                   // standard approach
    }
    console.log(elemInArr);
}

const arr = [1, 2, 3, 4];

logElementForLoop(arr);

Upvotes: 1

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