I get these timings on x86_64 GNU/Linux using the following profile program.
; A: cpu time: 7444 real time: 7445 gc time: 716 ; B: cpu time: 9227 real time: 9228 gc time: 884 (module profile racket/base (define target-length #e5e4) (define (A current-list new-element) (append current-list (list new-element))) (define (B current-list new-element) (reverse (cons new-element (reverse current-list)))) (define (profile function) (printf "~a: " (object-name function)) (time (void (for/fold ([l null]) ([n (in-range target-length)]) (function l n))))) (profile A) (profile B)) On 11/16/21 2:04 PM, David Storrs wrote: > If I want to add an element to the end of an immutable list, is it better to > do: > > (append current-list (list new-element)) > or > (reverse (cons new-element (reverse current-list))) > or > something else? > > I would imagine it's the first one because that should be a single traversal > and link add instead of two traversals and rebuilds, but maybe I'm wrong. > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > [https://groups.google.com/d/msgid/racket-users/CAE8gKocM4jNCg6xKruYwuwFtuOdbOSwugYcgUND1ZD%3DRB1iA0g%40mail.gmail.com](https://groups.google.com/d/msgid/racket-users/CAE8gKocM4jNCg6xKruYwuwFtuOdbOSwugYcgUND1ZD%3DRB1iA0g%40mail.gmail.com?utm_medium=email&utm_source=footer). -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/3a9777e7-4b33-b561-f47e-8fe940699b39%40sagegerard.com.
