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JavaScript JavaScript Loops, Arrays and Objects Tracking Data Using Objects The Build an Object Challenge, Part 2 Solution

Melinda Golden
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Melinda Golden
Full Stack JavaScript Techdegree Graduate 25,815 Points
Posted by Melinda Golden
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Melinda Golden
Full Stack JavaScript Techdegree Graduate 25,815 Points

I used a "for in" loop and my code works. Is the "for" loop better practice because it is an array of objects?

Here is my code: https://jsfiddle.net/mmgolden/jmtzqs8u/

2 Answers

Dan Oswalt
Dan Oswalt
23,438 Points
Dan Oswalt
Dan Oswalt
23,438 Points

For...in works for arrays, but it is not recommended. It's like using a deprecated method, sure it may work, but it's not really the right tool for the job, and you may get unexpected results. This is not the case for iterating over objects though, it's useful for that.

Dan Oswalt
Dan Oswalt
23,438 Points

And to add to the second part of your question, the contents of the array or object don't affect how you iterate over them.

John Stamps
John Stamps
1,712 Points
John Stamps
John Stamps
1,712 Points

Thank you, Dan. I did the same thing that Melinda did, because it was the last loop I remembered from the videos.

for (var property in students) { console.log(students[property]); html = document.getElementById("output").innerHTML; document.write(html += "<h2>Student: " + students[property].name + "</h2>"); document.write(html = "<p>Track: " + students[property].track + "</p>"); document.write(html = "<p>Achievements: " + students[property].achievements + "</p>"); document.write(html = "<p>Points: " + students[property].points + "</p><br>"); };

Dave created a separate student variable. Why create the separate variable? And why not use the for... in loop if we're indeed looping through objects?

Thanks in advance. I feel like I'm actually learning something!