Does dotimes force evaluation?,
if so, then the Clojure version is about twice as fast for me...
which would be nice to finally find a good dynamic programming
language that is also
nice and fast :-)
the code I tested is this:
(def HHQ [{:id 1956, :firstname "Piet", :lastname
"Puk", :programming_skills #{:java, :php, :closure}}
{:id 2000, :firstname "Blaat", :lastname
"Aap", :programming_skills #{:java, :php, :python}}
{:id 2020, :firstname "Jaap", :lastname
"Klaas", :programming_skills #{:cobol, :php, :skala}}])
(time
(dotimes [n 1000000]
(into {} (for [x HHQ :when ((x :programming_skills) :java)]
[(x :id) (str (x :firstname) " " (x :lastname))]))))
vs the python version
HHQ = [{'id': 1956, 'firstname': "Piet", 'lastname': "Puk",
'programming_skills': set(['java', 'php', 'closure'])},
{'id': 2000, 'firstname': "Blaat", 'lastname': "Aap",
'programming_skills': set(['java', 'php', 'python'])},
{'id': 2020, 'firstname': "Jaap", 'lastname': "Klaas",
'programming_skills': set(['cobol', 'php', 'skala'])}]
import time
start = time.time()
for i in range(1000000):
dict([(x['id'], (x['firstname'] + " " + x['lastname'])) for x in HHQ
if 'java' in x['programming_skills']])
end = time.time()
print end - start
On 14 okt, 19:09, Chris Perkins <[email protected]> wrote:
> On Oct 14, 11:54 am, Henk <[email protected]> wrote:
>
> > (I did some small benchmarks on this), while the list comprehension
> > itself is much faster than python...
>
> Not an answer to your question, but: depending on what you mean by
> "much faster", there is a good chance that you measured the clojure
> for expression doing nothing. You should wrap it in a doall or dorun
> to get a proper timing (like a generator in Python).
>
> Eg: for me, the following are almost exactly the same speed (~45ms):
>
> user=> (time (dorun (for [i (range 100000)] [i (* i i)])))
> "Elapsed time: 45.965679 msecs"
>
> C:\Users\chris>python -m timeit "[(i,i*i) for i in range(100000)]"
> 10 loops, best of 3: 45.5 msec per loop
>
> - Chris
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