Reap[expr] gives the value of expr together with all expressions to which Sow has been applied during its evaluation.
Expressions sown using Sow[e] or Sow[e, ] with different tags are given in different lists.
Reap[expr, patt] reaps only expressions sown with tags that match patt.
Reap[expr, , , ... ] puts expressions associated with each of in a separate list.
Reap[expr, patt, f] returns expr, f[, , , ... ], ... .
Sow and Reap provide a convenient way to accumulate a list of intermediate results in a computation.
Reap accumulates expressions in the order in which Sow is applied to them.
Expressions sown with a particular tag are collected by the innermost Reap whose pattern matches the tag.
Reap[expr] is equivalent to Reap[expr, _].
Reap has attribute HoldFirst.
See Section 2.4.1 and Section 2.6.10.
See also: Sow, Catch, AppendTo, Print.
New in Version 5.0.