BUILT-IN MATHEMATICA SYMBOL

Reap

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, tag_i] with different tags are given in different lists.

Reap[expr, patt]
reaps only expressions sown with tags that match patt.

Reap[expr, {patt₁, patt₂, ...}]
puts expressions associated with each of the in a separate list.

Reap[expr, patt, f]
returns .

Details Details

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.