Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

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

Posted by Igor Latychev
Igor Latychev
Courses Plus Student 7,310 Points

For Loops and Arrays in Javascript

Hey, i was wondering if you can help to understand how to exactly iterate through a list of values in an array using a for loop?

script.js 
var temperatures = [100,90,99,80,70,65,30,10];
for(var i = 100; i < temperatures.length; i -= 1) {
  console.log(temperatures[i]);
}
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

Jon Schiedermayer
Jon Schiedermayer
7,709 Points
Jon Schiedermayer
Jon Schiedermayer
7,709 Points

Your issue is in the loop conditions. You want your counter to retrieve the corresponding array position, so it's easiest to start with 0, which will correspond to the first item in your array. It is worth reading through this: https://www.w3schools.com/js/js_loop_for.asp

This will answer your question correctly, but it's worth understanding for loops.

var temperatures = [100,90,99,80,70,65,30,10];
for(i = 0; i < temperatures.length; i++){
  console.log(temperatures[i]);
}