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JavaScript JavaScript Loops, Arrays and Objects Tracking Multiple Items with Arrays Using For Loops with Arrays

Posted by Benjamin Bledsoe
Benjamin Bledsoe
10,900 Points

Specifics of a Function Question

Okay, at the end of the video, Dave mentions that you could create a function that takes an array as a parameter to average test scores. I decided to do this, and this is what I came up with:

var testScore = [ 97, 55, 87];


function averager( item ){
  var tally=0;
  var divideBy=0;
  for(var i=0; i < item.length; i += 1){
    tally+=item[i];
    divideBy +=1;
  }
  var answer = (tally/=divideBy);
  Math.floor(answer);
  return answer;
}

document.write(averager(testScore));

I have two main questions with this:

1) Why do I need to write '/=' to divide within the answer variable? I tried just using '/' and it didn't work, and I am very curious as to why.

2) Why is Math.floor(answer); not having effect of the final value of the answer variable?

I would greatly appreciate any explanations, and thank you in advance!

2 Answers

Joshua Edwards
Joshua Edwards
52,175 Points
Joshua Edwards
Joshua Edwards
52,175 Points

1) I got it to work just using '/' so I'm not sure why it did not work for you 2)You need to run Math.floor when you return answer or assign Math.floor(answer) to another variable that you then return. Math.floor doesn't change what is actually stored in the variable.

Benjamin Bledsoe
Benjamin Bledsoe
10,900 Points

Thank you, I guess I wasn't fully grasping the scope of storing data in variables with respect to this incident! Thanks for clearing that up!

Ryan Field
PLUS
Ryan Field
Courses Plus Student 21,242 Points
Ryan Field
Ryan Field
Courses Plus Student 21,242 Points

I also got it to work by using simply the division operator, but I'm not entirely sure why you're getting a float returned from your function. In any case, I tried the following code in my console, and it seemed to work fine:

var testScore = [ 97, 55, 87];


function averager( item ){
  var tally=0;
  var divideBy=0;
  for(var i=0; i < item.length; i += 1){
    tally+=item[i];
    divideBy +=1;
  }
  var answer = (tally/divideBy);

  return Math.floor(answer);

}

document.write(averager(testScore));
Benjamin Bledsoe
Benjamin Bledsoe
10,900 Points

Thanks man, I realized that I didn't use the floor method with return so it did not get stored in the variable