Try adding type hints. Assuming all-zips returns a list of strings:
(defn all-zips-MD5 []
"Returns a lazy list of all possible American zipcodes, as MD5
digests."
(let [digester (java.security.MessageDigest/getInstance "MD5")]
(map
(fn [#^java.util.String to-digest]
(.update digester (.getBytes to-digest))
(String. (.digest digester)))
(all-zips))))
I think this will work. You might have to explicitly define the
mapping function.
On Jun 5, 10:56 am, Daniel Jomphe <danieljom...@gmail.com> wrote:
> I need to generate a list of all possible American zipcodes, MD5-
> digested. Later on, I will need to do much more involving stuff,
> processor-wize, with this. But already, generating a naive list of all
> possible zipcodes is taking quite a deal of time:
>
> user> (time (dorun (take 1000000 (all-zips))))
> "Elapsed time: 3294.478 msecs"
> nil
> user> (time (dorun (take 1000000 (all-zips-MD5))))
> "Elapsed time: 28150.076 msecs"
> nil
>
> If I allow the whole all-zips to be realized, it takes nearly 1 hour.
> I have tried a few optimizations, but before proceeding any further
> with it, I wondered if you'd have any advice re: idiomatic clojure and
> optimization.
>
> Here's my code:
>
> (defn all-zips-MD5 []
> "Returns a lazy list of all possible American zipcodes, as MD5
> digests."
> (let [digester (java.security.MessageDigest/getInstance "MD5")]
> (map
> (fn [to-digest]
> (.update digester (.getBytes to-digest))
> (String. (.digest digester)))
> (all-zips))))
>
> (defn all-zips []
> "Returns a lazy list of all possible American zipcodes."
> (let [zips5 (zip-formatted-range 5)
> zips4 (zip-formatted-range 4)
> cross-prod-zips4 (fn [zip5] (map #(str zip5 "-" %) zips4))
> zips5-4 (mapcat cross-prod-zips4 zips5)]
> (concat zips5 zips5-4)))
>
> (defn zip-formatted-range [n-digits]
> "Returns a lazy list of stringified numbers, which are pre-padded
> with zeroes, starting from 0 and going up to the max number that can
> be represented with a number of digits of n-digits. Thus, if n-digits
> is 3, it will produce [001, 002, ... 999]."
> (let [zip-formatter #(format (str "%0" n-digits "d") %)
> n-to-format (Math/pow 10 (dec n-digits))
> n-max (Math/pow 10 n-digits)]
> (concat (map zip-formatter (take n-to-format (range n-max)))
> (map str (drop n-to-format (range n-max))))))
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