Comments for The Free Geek

Comment on 10 Clojure One Liners to Impress Your Friends by mchampine

mchampine — Tue, 27 Dec 2011 04:20:15 +0000

A favorite “impress your friends” one-liner of mine is:

(time (nth (map first (iterate (fn [[a b]] [b (+ a b)]) [0 1])) 100000))

Which outputs the gigantic 20899 digit number which is the 100000th value of the fibonacci sequence. The timer shows how fast it ran. On my nothing-special core i5 I got “Elapsed time: 792.022986 msecs”.

Comment on Clojure Protocols & Datatypes — A sneak peek by Pankaj Doharey

Pankaj Doharey — Thu, 24 Nov 2011 13:34:08 +0000

In ruby a statistical mode could be something as small as this :

p ARGV.collect {|i| [ARGV.count(i) , i]}.sort.last.last ,

which includes taking a input from command line … can something similar be done in clojure. the above could could handle everything but floats. for floats we can use this.

p ARGV.uniq.map {|i| [ARGV.count(i) , (i.to_f == i.to_f.floor) ? i.to_i : i.to_f]}.sort.last.last

this new line can handle everything mixed strings floats , negatives and return a statistical mode.

Comment on Clojure Protocols & Datatypes — A sneak peek by Pankaj Doharey

Pankaj Doharey — Thu, 24 Nov 2011 13:30:25 +0000

How to write a smallest statistical mode in clojure ? like for a series like :

# 1 2 3 4 5 2 4 8 9 0 1 5 3 6 6 7 0 — normal series.
# 1 2.0 3 4.1 5 2.3 4 8 9 0 1 5 3.2 6 6 7 0 -1 -3 -5 -2 -1 — mixed series with floats and negatives. What could be the shortest one liner for this ?

Comment on Clojure Protocols & Datatypes — A sneak peek by David

David — Fri, 21 Oct 2011 19:43:59 +0000

Thanks for the nice explanation of protocols! I wasn’t getting it before. I think I got it now. Keep the posts coming!

Comment on Clojure Protocols & Datatypes — A sneak peek by Sidharth

Sidharth — Wed, 28 Sep 2011 10:04:08 +0000

Best explanation of reify, defrecord and defprotocols!

It might be a good idea to show explictly that you can call (fly crow) if you simply used extend-type

Thanks!

Comment on 10 Clojure One Liners to Impress Your Friends by mnicky

mnicky — Thu, 15 Sep 2011 14:04:39 +0000

@mx: a little shorter, but more dumb and memory-consuming:

((fn[n](reduce(fn[c x](filter #(or(< 0(mod % x))(= % x))c))n n))(range 2 100))

and uncompressed:

((fn [numbers]
(reduce (fn [coll number]
(filter #(or (< 0 (mod % number)) (= % number))
coll))
numbers
numbers))
(range 2 100))

Comment on 10 Clojure One Liners to Impress Your Friends by mx

mx — Mon, 29 Aug 2011 15:15:07 +0000

10.
((fn sieve [numbers primes]
(if (empty? numbers) (reverse primes)
(sieve (filter #(> (mod % (first numbers)) 0) numbers) (cons (first numbers) primes)))
) (range 2 100) ())

Comment on 10 Clojure One Liners to Impress Your Friends by Manoj Waikar

Manoj Waikar — Mon, 08 Aug 2011 18:33:15 +0000

Hi BG,

I am a little confused by Aaron’s comments on clojure.contrib being deprecated. If it is deprecated, what is the equivalent of clojure.contrib.java-utils? I specifically want to use read-properties function.

Also why is this (http://clojure.github.com/clojure-contrib/branch-master/java-utils-api.html) still available under v 1.3?

Thanks,
Manoj.

Comment on 10 Clojure One Liners to Impress Your Friends by Baishampayan Ghose

Baishampayan Ghose — Tue, 14 Jun 2011 09:46:54 +0000

Jaskirat: I try to avoid using `apply` when the operation is inherently binary in nature (eg. +,-,max, etc.).

If you look at the definition of `max` you will see that it uses `reduce` when the arity is more than 2

Comment on 10 Clojure One Liners to Impress Your Friends by Jaskirat

Jaskirat — Tue, 14 Jun 2011 09:34:59 +0000

Nice! I just had one little question, do you have any particular reason for not using apply instead of reduce for question 8 ?
(apply max [1 2 3])

@Chris
That’s a neat way to transpose a matrix!