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Re: finding the position of a pattern in list

  • To: mathgroup at smc.vnet.net
  • Subject: [mg64624] Re: finding the position of a pattern in list
  • From: "dennis" <dwangsness at earthlink.net>
  • Date: Fri, 24 Feb 2006 00:18:23 -0500 (EST)
  • References: <dtjjcv$de7$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

The Partition function combined with Position works.

if d is your data and pat is your pattern try

Position[Partition[d,2,1],pat]

You can Flatten the result to get rid of the brackets if you want.

Dennis

Gang Ma wrote:
> Hi,
> I am working on a program to do the following: My data is a list of 0
> and 1. For example, {0,0,1,1,1,0,0,1,1,1,0}. I want to find the
> positions of all the pattern of {0,1}.  In my previous example, the
> first {0,1} is at 2 and and the second {0,1} appears at 7. I can
> write a loop to do this, but I have several thousands such lists,
> the computation will be time consuming using loop.
>
> My question is whether it is possible to use the pattern match to do
> this quickly.  If not for the list, do I need to convert the list to
> string then use some pattern match for string?  Thank you very much.
> 
> regards,
> 
> Gang Ma


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