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JavaScript JavaScript Loops, Arrays and Objects Tracking Multiple Items with Arrays Iterating through an Array

Posted by Amir Abaza
Amir Abaza
12,713 Points

Need help

Stuck on this JavaScript task...

script.js 
var temperatures = [100,90,99,80,70,65,30,10];

function print(message) {
    document.write(message);
}

function printList(list) {
    var listTemp;
  for(var i=0; i<list.length; i+=1)
        listTemp +=  list[i] + ' ';
}

printList(temperatures);
index.html 
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript Loops</title>
</head>
<body>
<script src="script.js"></script>
</body>
</html>

1 Answer

Alex Koumparos
seal-mask
.a{fill-rule:evenodd;}techdegree
Alex Koumparos
Python Development Techdegree Student 36,887 Points
Alex Koumparos
.a{fill-rule:evenodd;}techdegree
Alex Koumparos
Python Development Techdegree Student 36,887 Points

Hi Amir,

You have a few problems here. The first issue is that you have written a print function to write things to the document (i.e., into the body of the webpage). However, the challenge instructions don't ask you to write anything into the webpage, they ask you to log to the console:

Inside the loop, log the current array value to the console.

That said, your function doesn't actually send the temperature values anywhere, since your printList function gets the temperatures from the array and adds them to a listTemp variable but never actually returns the listTemp variable (so your print function ends up printing nothing).

If you did return your listTemp variable at the end of the function, you would notice that it doesn't correctly represent the data you want to return. You have a leading undefined and a trailing space, neither of which you are asked to log to the console (The undefined comes from using the += operator with a variable that has been declared but has not been assigned a value; the trailing space comes from adding ' ' to every number in the array, including the last one).

As it turns out, these are both easy to fix, since you don't need to build up a listTemp variable at all. Going back to the challenge instructions we see:

Inside the loop, log the current array value to the console.

That is, every time you are in the body of the loop, just log the current value.

Hope that clears things up.

Cheers,

Alex