On Mon, Sep 22, 2008 at 10:26 AM, Sylvain Joyeux <sylvain.joyeux / polytechnique.org> wrote: > Nope. each { } needs one new scope for each iteration while "for ... in" > explicitely uses the parent scope... In the end, you create with #each > as many objects as there are in your collection - which can be a huge > performance hit in some cases. In what sense does #each create objects? Assuming a block with just one parameter, you mean there's a new reference to existing objects per iteration? May that impact that much GC?