From: rantingrick on 6 Jun 2010 11:16 Everyone knows i'm a Python fanboy so nobody can call me a troll for this... Python map is just completely useless. For one it so damn slow why even bother putting it in the language? And secondly, the total "girl- man" weakness of lambda renders it completely mute! Ruby has a very nice map >>> [1,2,3].map{|x| x.to_s} Have not done any benchmarking but far more useful from the programmers POV. And that really stinks because map is such a useful tool it's a shame to waste it. Here are some test to back up the rant. >>> import time >>> def test1(): l = range(10000) t1 = time.time() map(lambda x:x+1, l) t2= time.time() print t2-t1 >>> def test2(): l = range(10000) t1 = time.time() for x in l: x + 1 t2 = time.time() print t2-t1 >>> test1() 0.00200009346008>>> test2() 0.000999927520752>>> def test3(): l = range(10000) t1 = time.time() map(str, l) t2= time.time() print t2-t1 >>> def test4(): l = range(10000) t1 = time.time() for x in l: str(x) t2= time.time() print t2-t1 >>> test3() 0.00300002098083>>> test4() 0.00399994850159>>> So can anyone explain this poor excuse for a map function? Maybe GVR should have taken it out in 3.0? *scratches head* From: James Mills on 6 Jun 2010 11:33 On Mon, Jun 7, 2010 at 1:16 AM, rantingrick wrote:> So can anyone explain this poor excuse for a map function? Maybe GVR > should have taken it out in 3.0? Â *scratches head* Let me get this straight... You're complaining about some trivial code you've written and a 0.002 or less execution time ? I must be missing something! --James From: Roald de Vries on 6 Jun 2010 12:28 On Jun 6, 2010, at 5:16 PM, rantingrick wrote:> Everyone knows i'm a Python fanboy so nobody can call me a troll for > this... > > Python map is just completely useless. For one it so damn slow why > even bother putting it in the language? And secondly, the total "girl- > man" weakness of lambda renders it completely mute! > > Ruby has a very nice map > >>>> [1,2,3].map{|x| x.to_s} > > Have not done any benchmarking but far more useful from the > programmers POV. And that really stinks because map is such a useful > tool it's a shame to waste it. Here are some test to back up the rant. > > >>>> import time >>>> def test1(): > l = range(10000) > t1 = time.time() > map(lambda x:x+1, l) > t2= time.time() > print t2-t1 > > >>>> def test2(): > l = range(10000) > t1 = time.time() > for x in l: > x + 1 > t2 = time.time() > print t2-t1 > > >>>> test1() > 0.00200009346008 >>>> test2() > 0.000999927520752 >>>> def test3(): > l = range(10000) > t1 = time.time() > map(str, l) > t2= time.time() > print t2-t1 > > >>>> def test4(): > l = range(10000) > t1 = time.time() > for x in l: > str(x) > t2= time.time() > print t2-t1 > > >>>> test3() > 0.00300002098083 >>>> test4() > 0.00399994850159 >>>> > > So can anyone explain this poor excuse for a map function? Maybe GVR > should have taken it out in 3.0? *scratches head* Use list comprehension. It's nicer than Ruby's map: [x.to_s for x in 1, 2, 3] From: Duncan Booth on 6 Jun 2010 12:32 rantingrick wrote: > Python map is just completely useless. For one it so damn slow why > even bother putting it in the language? And secondly, the total "girl- > man" weakness of lambda renders it completely mute! Do you realise that you don't have to use lambda? If you need more than a single expression just create a named function. From: Alain Ketterlin on 6 Jun 2010 13:02 rantingrick writes: > Python map is just completely useless. [...] >>>> import time >>>> def test1(): > l = range(10000) > t1 = time.time() > map(lambda x:x+1, l) > t2= time.time() > print t2-t1 >>>> def test2(): > l = range(10000) > t1 = time.time() > for x in l: > x + 1 > t2 = time.time() > print t2-t1 > >>>> test1() > 0.00200009346008 >>>> test2() > 0.000999927520752 >>>> def test3(): Well, not building the resulting list saves some time. But even if you do r.append(x+1) map appears to be slower... Try this: def test3(): l = range(10000) t1 = time.time() [ x+1 for x in l] t2 = time.time() print t2-t1 I've not used map since I learned about list comprehensions. -- Alain.  |  Next  |  Last Pages: 1 2 3 4 Prev: Sniffer Linux with Raw SocketNext: Drop Table w/ MySQLdb?