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Re: Delete elements from list..

  • To: mathgroup at smc.vnet.net
  • Subject: [mg117027] Re: Delete elements from list..
  • From: Peter Pein <petsie at dordos.net>
  • Date: Tue, 8 Mar 2011 05:34:11 -0500 (EST)
  • References: <ijv047$68v$1@smc.vnet.net> <ik00i6$e6k$1@smc.vnet.net> <il2dau$66o$1@smc.vnet.net>

Am 07.03.2011 11:51, schrieb BoLe:
> On Feb 22, 10:44 am, Ray Koopman<koop... at sfu.ca>  wrote:
>>
>> Union@FoldList[Max,First@mylist,Rest@list]
>>
>
> Wov, that is elegant to me, and fast. DeleteDuplicates speeds it a
> tiny bit up. ;-) Since Union sorts the result (already sorted in this
> case) or does it do something else too?
>

DeleteDuplicates is much slower here:

In[9]:= mysecondlist=RandomInteger[{0,99},{2000}];
In[10]:= 
Timing[Do[u1=Union@FoldList[Max,First@mysecondlist,Rest@mysecondlist],{1000}];u1]

Out[10]= {1.139,{79,98,99}}

In[11]:= Timing[Do[u2=DeleteDuplicates[mysecondlist,#2<=#1&],{1000}];u2]
Out[11]= {33.026,{79,98,99}}

Peter

P.S.: This computer has been slowed down due to thermal problems.


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