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

Posted by Adam White
Adam White
10,571 Points

Why is my "Using For Loops with Arrays" code not working?

Hi. I've checked and checked my code to see if it matches the instructors, but I can't find any difference. I keep getting "NaNMaybellene" when I preview. Note: the code I added begins at "function printList( list ). Thanks.

var playList = [
  'I Did It My Way',
  'Respect',
  'Imagine',
  'Born to Run',
  'Louie Louie',
  'Maybellene'
];

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

function printList( list ) {
    var listHTML ='<ol>';
    for ( var i = 0; i < list.length; i += 1) {
    listHTML =+ '<li>' + list[i] + '</li>';
    }   
    listHTML += '</ol>';    
    print(listHTML);
}

printList (playList);
Andrews Gyamfi
Andrews Gyamfi
Courses Plus Student 15,658 Points

The error is in the for loop construct where you have "listHTML =+" instead of "listHTML +=" i.e the plus symbol should come before the equal to symbol. I believe it was just a typo as you have it written correctly in other lines.

Cheers!

4 Answers

Andrews Gyamfi
Andrews Gyamfi
Courses Plus Student 15,658 Points

The error is in the for loop construct where you have "listHTML =+" instead of "listHTML +=" i.e the plus symbol should come before the equal to symbol. I believe it was just a typo as you have it written correctly in other lines.

Cheers!

Jonathan Grieve
MOD
Jonathan Grieve
Treehouse Moderator 91,253 Points
Jonathan Grieve
Jonathan Grieve
Treehouse Moderator 91,253 Points

On line 17 try changing your operator from =+ to += so it matches the rest of them. What you're doing at the moment is assigning a new straight value rather than adding to the variable. :-)

listHTML += '<li>' + list[i] + '</li>';
Andrews Gyamfi
PLUS
Andrews Gyamfi
Courses Plus Student 15,658 Points
Andrews Gyamfi
Andrews Gyamfi
Courses Plus Student 15,658 Points

The error is in the for loop construct where you have "listHTML =+" instead of "listHTML +=" i.e the plus symbol should come before the equal to symbol. I believe it was just a typo as you have it written correctly in other lines.

Cheers!

Adam White
Adam White
10,571 Points
Adam White
Adam White
10,571 Points

Thanks to both of you. The Typo Bandit strikes again!

Andrews Gyamfi
Andrews Gyamfi
Courses Plus Student 15,658 Points

Welcome :)