array without an index always expands to the element in the index 0 (saying "the first element" is not accurate)

SC2128.md

@@ -1,4 +1,4 @@
-## Expanding an array without an index only gives the first element.
+## Expanding an array without an index only gives the element in the index 0.
 
 ### Problematic code:
 
@@ -22,7 +22,7 @@ done
 
 ### Rationale:
 
-When referencing arrays, `$myarray` is equivalent to `${myarray[0]}` -- it results in only the first of multiple elements.
+When referencing arrays, `$myarray` is equivalent to `${myarray[0]}` -- which is usually the first of multiple elements. This is also true for associative arrays. Therefore, if 0 (zero) is not a valid key, `$myarray` expands to an empty string.
 
 To get all elements as separate parameters, use the index `@` (and make sure to double quote). In the example, `echo "${myarray[@]}"` is equivalent to `echo "foo" "bar"`.