As for length: (for ([i 3]) (collect-garbage)) (let ((ls (time (make-list 50000000 0)))) (time (length ls)) (time (length ls)) (time (length ls)) (void))
It's what I would expect: cpu time: 6733 real time: 6744 gc time: 6419 cpu time: 141 real time: 141 gc time: 0 cpu time: 145 real time: 145 gc time: 0 cpu time: 142 real time: 142 gc time: 0 - - - - - Next, thinking about 50000000 elements made me think about vectors, vector? and vector-length. This: (for ([i 3]) (collect-garbage)) (let ((v (time (make-vector 50000000 0)))) (time (vector-length v)) (time (vector-length v)) (time (vector-length v)) (void)) prints: cpu time: 182 real time: 183 gc time: 1 cpu time: 315 real time: 315 gc time: 314 cpu time: 0 real time: 0 gc time: 0 cpu time: 0 real time: 0 gc time: 0 Huh? The first call to vector-length takes even longer than making the vector (and, seems to be almost entirely gc). I would have guessed that make-vector would create a structure with the length already stored in it, and all vector-length calls would be essentially 0. ____________________ Racket Users list: http://lists.racket-lang.org/users
