bug? #'separate in seq-utils
reynard
ok, the following works as expected.
user> (separate (fn [n]
(= n 2))
'(1 2 3 4 5))
[(2) (1 3 4 5)]
now, I want to randomly select a number from '(1 2 3 4 5), I change
the function to the following, and the result is NOT expected.
user> (separate (fn [n]
(= n (inc (int (rand 5)))))
'(1 2 3 4 5))
[() (2 3 4)]
Is it a bug in the separate function or do I use it incorrectly?
Stuart Halloway
match, and a vector of things that don't match. Every time you call
the function it matches against a different random number. Take a look
at rand-elt in clojure.contrib.seq-utils.
Maybe the docstring for separate should say that fn should be side-
effect-free...
Stu
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reynard
On Feb 18, 10:51 pm, Stuart Halloway <stuart.hallo...@gmail.com>
wrote:
> You are using it incorrectly. Separate returns a vector of things that
> match, and a vector of things that don't match. Every time you call
> the function it matches against a different random number. Take a look
> at rand-elt in clojure.contrib.seq-utils.
Yes, the problem is solved by first binding the result of the random
number, before applying it inside #'separate, as follows, thanks
user> (let [rand-num (inc (int (rand 5)))]
(separate (fn [n]
(= n rand-num))
'(1 2 3 4 5)))
[(4) (1 2 3 5)]
> Maybe the docstring for separate should say that fn should be side-
> effect-free...
I concur.