A list is simply a list of things. The list has no
structure, except in some cases, the length of the list may be
known. The list may contain duplicate items. In the following
example the number 1 is included twice.
1 2 3 1
A set is similar to a list, but has the following differences:
- The size of the set is always known
- A set may not contain duplicates
You can convert a list to a set by creating a 'weighted
list'. The weighted list includes a
count column so that you can determine when an
item in the list appears more than once:
1,2 2,1 3,1
Notice that there are two number 1 values in the weighted list.
In order to make insertions into such a list scalable, consider
using partitioning to avoid large indexes.