On Thu, Dec 25, 2008 at 12:39:24PM -0500, Mark J. Reed wrote: > On Thu, Dec 25, 2008 at 12:00 PM, Patrick R. Michaud <pmich...@pobox.com> > wrote: > > On Thu, Dec 25, 2008 at 12:53:06AM -0500, Mark J. Reed wrote: > >> I also tried this, but it caused Rakudo to throw a StopIteration and > >> then segfault: > >> > >> for [...@gifts[0..$day-1]].pairs.reverse -> $n, $g > > > > The StopIteration occurs when there aren't enough elements in the > > list to supply to the parameters to the body. In the example above, > > it would occur whenever there are an odd number of pairs. > > OK, so that loops through the list in groups of two. So how do I Ioop > through a list of Pairs assigning the key to one var and the value to > another? It's not a Hash, and calling .kv on it yields 0=>first pair, > 1=>second pair, etc... I don't want to Hashify it because I want to > preserve the order...
Extracting the keys+values from a list of Pairs was a question that occurred to me as well when implementing it... I don't know the answer to that. However, for this specific problem, perhaps the zip operator is a better choice anyway: for (^$day Z @gifts).reverse -> $g, $n { ... } I'm not entirely sure of the order of the $g, $n arguments here, or exactly how .reverse chooses to change the order of the items produced by infix:<Z> (does it flatten or no?). But some permutation of this should work. Pm