title: Create a collection (array) in SASS for use in @for loop
body: <p>I'm learning <strong>SASS</strong> and I'm trying to pass a collection of data (an <strong>array</strong>) into a <code>@mixin</code> and process based on that. The trouble I'm having is defining the <strong>data structure</strong> to pass the values into the <code>@mixin</code></p>
  
  <p>Here's some pseudo code:</p>
  
  <pre>
  <code>@mixin roundcorners($collection) {
  
      $collectionLength = length(collection);
  
      @for($i from 0 to $collectionLength) {
          border-#{$collection[$i]}-radius: 9px;
      }
  
  }
  
  .mybox {
  
      @include roundcorners(['top-right','bottom-left']);
  
  }</code>
  </pre>
  
  <p>The desired output would be this:</p>
  
  <pre>
  <code>.mybox {
      border-top-right-radius: 9px;
      border-bottom-left-radius: 9px;
  }</code>
  </pre>