An array has a changeable length.  A list does not.  An
       array is something you can push or pop, while a list is a
       set of values.  Some people make the distinction that a
       list is a value while an array is a variable.  Subroutines
       are passed and return lists, you put things into list con-
       text, you initialize arrays with lists, and you foreach()
       across a list.  "@" variables are arrays, anonymous arrays
       are arrays, arrays in scalar context behave like the num-
       ber of elements in them, subroutines access their argu-
       ments through the array "@_", and push/pop/shift only work
       on arrays.

       As a side note, there's no such thing as a list in scalar
       context.  When you say

           $scalar = (2, 5, 7, 9);

       you're using the comma operator in scalar context, so it
       uses the scalar comma operator.  There never was a list
       there at all!  This causes the last value to be returned:
       9.