Explain Lists and iValue.

Lists are special types of arrays that hold a series of values. The list can be explicitly generated by the user, or it can be a value returned by a function. Users can generate it using parenthesis and comma to separate the values.
If you want to store the result of any expression, then iValues are used. These are scalar values which are found on the left-side of the expression. It represents the data space in the memory.