Re: Extracting information from lists
- To: mathgroup at smc.vnet.net
- Subject: [mg63353] Re: [mg63323] Extracting information from lists
- From: "Barthelet, Luc" <lucb at ea.com>
- Date: Sat, 24 Dec 2005 16:03:00 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
I suspect you already got many answers, but this is one more:
First /@ Cases[
Transpose[{Most[FoldList[Plus, 1, Length[#] & /@ Split[list]]],
Split[list]}]
, {_, {x__}} /; x == 1]
{3, 6, 10, 16}
-----Original Message-----
From: Tony King [mailto:mathstutoring at ntlworld.com]
To: mathgroup at smc.vnet.net
Subject: [mg63353] [mg63323] Extracting information from lists
Does anyone know of a function that will allow me to extract the
positions
of the first elements of runs of similar elements within a list. For
example, suppose that
list={7,9,1,6,8,1,1,6,5,1,1,1,8,7,6,1,1,1,1,7}
I need a function that will return
{3,6,10,16}
corresponding to the runs {1},{1,1},{1,1,1},{1,1,1,1} within list
Many thanks
Tony