AppendTo[s, elem] appends elem to the value of s, and resets s to the result.
AppendTo[s, elem] is equivalent to s = Append[s, elem].
AppendTo[s, elem] does not evaluate s.
You can use AppendTo repeatedly to build up a list, though Sow and Reap will usually be more efficient.
AppendTo works on SparseArray objects, returning ordinary lists if necessary.
See Section 2.5.4.
See also: PrependTo, Sow.
New in Version 1.