Clojure 1.2 has a shuffle function. If you're using 1.1, you can just
cop the 1.2 implementation.

On Jul 21, 1:18 pm, Ryan Waters <[email protected]> wrote:
> http://gist.github.com/484747
>
> - - -
>
> My sad little program has a number of issues and I would welcome
> suggestions on any aspect of it.  I come from an imperative
> programming background and clojure is my first experience with a
> functional or lisp language.
>
> I'd like to take a list of things (really, a vector) and randomly add
> items of that list to another list.  I chose to work with vectors
> because clojure is efficient at adding things their ends and because I
> can address their consistent ordering with an index.
>
> Issues:
>
> 1) Idiomatic: please point out anything that looks generally awkward
> or otherwise less than ideal for clojure (and suggest an alternative)
> : )  For example, in my loop I rebind symbols to themselves and have
> received mixed advice on IRC as to whether it's appropriate to do
> that.
>
> 2) Transients: For speed and because I don't care about the
> intermediate values of the vectors, I'd like to use them.  I was able
> to easily work with the transient vector 'random-ips' but receive an
> error when trying to wrap the vector 'ordered-ips' in a transient:
> "Exception in thread "main" java.lang.ClassCastException:
> clojure.lang.PersistentVector$TransientVector cannot be cast to
> clojure.lang.IPersistentVector (gen_ips.clj:36)"
>
> 3) Overall speed: it's abysmal but I don't blame Clojure.  It's either
> because I'm Doing It Wrong or what I'm doing is simply expensive in a
> big O notation sort of way.  I'm trying to randomly order 1.1 million
> strings.
>
> 4) Clojure side-gripe: I wish it were easier to mix clojure's
> different 'types': vectors, lazy sequences, etc.  It's probably an
> ignorance thing on my part but, for what I know right now, I find
> using different macros with all the different return types
> problematic.
>
> - - -
>
> Thanks in advance to addressing one or more of these issues!
>
> - Ryan

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