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JavaScript JavaScript Loops, Arrays and Objects Tracking Multiple Items with Arrays Two-Dimensional Arrays

Posted by Minh Pham
Minh Pham
1,181 Points

function print(message) ?

I don't understand why do we need a function print(message) here. Why do we use 'message' as a parameter and what will this function do because we also have function printSongs below

Julia Ji
Julia Ji
13,266 Points
Julia Ji
Julia Ji
13,266 Points

Hi Minh,

I really like the instructor but I found that part confusing too. I just coded it this way. It's a lot easier to understand.

var playList = [ ['I Did It My Way', ' Frank Sinatra'], ['Respect', ' Aretha Franklin'], ['Imagine', ' John Lennon'], ['Born to Run', ' Bruce Springsteen'], ['Louie Louie', ' The Kinsmen'], ['Maybellene', ' Chuck Berry'] ];

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

// I just removed the entire print method and replaced it with this.
document.write((listHTML)); }

printList(playList);

2 Answers

richporter
richporter
16,727 Points
richporter
richporter
16,727 Points

You don't need a print function here, but it provides reusable, flexible code for the future.

The message parameter could be called anything, but message is suitable so we know to pass it the message/string we want it to work with.

In the video, Dave uses the printSongs function to construct a list of songs (hence the name of the function) as a string. Notice normally it wouldn't print or return anything.

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

Now, after constructing the list, he calls the print function to print out the listHTML string.

print(listHTML);
Conor Vanoystaeyen
Conor Vanoystaeyen
16,687 Points
Conor Vanoystaeyen
Conor Vanoystaeyen
16,687 Points

( function print) is a print function where you give a parameter and prints it. And (function printSongs) returns an unordered list of songs. But why you need the print function is something you have to watch the video for they will say why they use it. Because making useless functions is bad coding and they do not teach you that. Hope this helps. :)