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JavaScript JavaScript Loops, Arrays and Objects Simplify Repetitive Tasks with Loops The Refactor Challenge, Part 2

Jeffrey Huang
Jeffrey Huang
5,914 Points
Posted by Jeffrey Huang
Jeffrey Huang
5,914 Points

Alternative? For-loop inside a for-loop

Hi I was wondering why this code doesn't.

var html = ''; var rgbColor = 'rgb(';

function colorNumber() { return Math.floor(Math.random() * 256 ); }

for (var i=0; i<10; i++) { for (var j=0; j<3; j++) { j = colorNumber(); rgbColor += j if (j < 2) { rgbColor += ','; } else { rgbColor += ')'; } } html += '<div style="background-color:' + rgbColor + '"></div>'; }

document.write(html);

There was also a mention of alternative solutions. Is anyone able to show them?

(Sorry it's not set out properly. I couldn;t find any button that lets me attach code through treehouse so I had to copy and paste)

1 Answer

Corina Meyer
Corina Meyer
9,990 Points
Corina Meyer
Corina Meyer
9,990 Points

First, why your code might not work as expected:

  • the rgbColor variable should be declared inside the outer for loop
  • the counter variable (j) is also used to get a colorNumber, this overwrites the counter

Another possibility to write this without two for-loops 

var html = '',
    rows = 10;

function colorNumber() {
  return Math.floor(Math.random() * 256);
}

function rndColor() {
  var rgb = [colorNumber(), colorNumber(), colorNumber()];
  return 'rgb(' + rgb.join(', ') + ')';
}

for(var c = 0; c < rows; c++) {
  html += '<div style="background-color: ' + rndColor() + '"></div>';
}

document.write(html);

and if you want to learn about markdown (the treehouse markdown cheatsheet seams to no longer be available), you could google for "markdown cheatsheet". i would link one here, but i don't think that would be allowed?

Jeffrey Huang
Jeffrey Huang
5,914 Points
Jeffrey Huang
Jeffrey Huang
5,914 Points

Ahh okay that makes sense. I guess I'd have to apply javascript to be learnt in further sessions to be able to complete it in other alternative methods.

Thank you!