Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.7)
// Compass (v1.0.1)
// ----

$list: (
  (a: ".div-1", b: (a: 100px)),
  (a: ".div-2", b: (a: 200px)),
  (a: ".div-3", b: (a: 300px)),
);

@each $item in $list {
  $selector: map-get($item, a);
  $width: map-get(map-get($item, b), a);
  
  #{$selector} {
    width: $width;
  }
}

SassMeister-output.css

.div-1 {
  width: 100px;
}

.div-2 {
  width: 200px;
}

.div-3 {
  width: 300px;
}