Re: position of sequence of numbers in list

*To*: mathgroup at smc.vnet.net*Subject*: [mg107007] Re: position of sequence of numbers in list*From*: "Steve Luttrell" <steve at _removemefirst_luttrell.org.uk>*Date*: Sun, 31 Jan 2010 05:58:23 -0500 (EST)*References*: <hk17lo$ogf$1@smc.vnet.net>

I don't know about efficiency, but here is another way of doing what you want: {1, 2, 3, 4, 5} /. {u___, 3, 4, ___} :> Length[{u}] + 1 -- Stephen Luttrell West Malvern, UK "JB" <jkerrb at gmail.com> wrote in message news:hk17lo$ogf$1 at smc.vnet.net... > Hi, > > What is the most efficient way to find the position of the beginning > of a sequence of numbers from a list? > > I found a couple of ways: > > find 3,4 in list={1,2,3,4,5}; > > 1. pos=Intersection[Position[list,3],(Position[list,4])+1] > > 2. pos=Position[Partition[list,2,1],{3,4}] > > Are there other ways to do this? > What is the best way when dealing with large lists? > > Thanks, > JB >

**Follow-Ups**:**Re: Re: position of sequence of numbers in list***From:*Leonid Shifrin <lshifr@gmail.com>