Re: Fast List-Selection

*To*: mathgroup at smc.vnet.net*Subject*: [mg19922] Re: [mg19880] Fast List-Selection*From*: Carl Woll <carlw at u.washington.edu>*Date*: Tue, 21 Sep 1999 02:22:53 -0400*Organization*: Physics Department, U of Washington*References*: <199909192247.SAA12942@smc.vnet.net.>*Sender*: owner-wri-mathgroup at wolfram.com

Hi Hans, Here is one idea: rep[ls_]:=Position[Partition[ls,7,1],{x_ ..}] For a 10000 element random list of integers (0,1,2), it took less than a second. It'll be interesting to see the other solutions. Carl Woll Physics Dept U of Washington Hans Havermann wrote: > I have a list 's' composed of a large number of (small) integers. I wish to > search this list for instances of 7 consecutive, identical elements. > > My approach is: > > Do[If[Count[t = Take[s, {i, i + 6}], t[[1]]] == 7, > Print[i]], {i, 1, Length[s] - 6}] > > Can anyone think of a *faster* way of doing this?

**References**:**Fast List-Selection***From:*Hans Havermann <haver@total.net>