Re: Re: position of sequence of numbers in
- To: mathgroup at smc.vnet.net
- Subject: [mg107018] Re: [mg107005] Re: [mg106976] position of sequence of numbers in
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Sun, 31 Jan 2010 08:18:38 -0500 (EST)
- Reply-to: hanlonr at cox.net
This is wrong. I obviously didn't test this. Instead, use
myList = {3, 1, 2, 5, 3, 4, 6, 2, 8, 9, 3, 4}
{3,1,2,5,3,4,6,2,8,9,3,4}
Select[Position[myList, 3],
MemberQ[Position[myList, 4] - 1, #] &]
{{5}, {11}}
Bob Hanlon
---- Bob Hanlon <hanlonr at cox.net> wrote:
=============
Position[list, Sequence[3, 4]]
Bob Hanlon
---- JB <jkerrb at gmail.com> wrote:
=============
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