Finding lengths of identical sequences in lists

*To*: mathgroup at smc.vnet.net*Subject*: [mg20240] Finding lengths of identical sequences in lists*From*: Joel Cannon <jcannon at jcannon.washjeff.edu>*Date*: Fri, 8 Oct 1999 18:30:16 -0400*Sender*: owner-wri-mathgroup at wolfram.com

I am looking for a more elegant solution to the following. I have a list (a list of positions at consecutive times). I wish to create a new list of the length of each sequence of consecutive identical members (including those of length 1). For example, for the list {3,2,2,3,3,3,1} I would create the list {1,2,3,1} because the first 3 appears once, followed by two 2's, etc. The lists I was working with contained a list of numbers (e.g. {{x1,y1},{x2,y2},...} rather than simple numbers. I accomplished this using a while loop, but I suspect there are better ways to do this using pattern matching or other approaches. Thanks much. ------------------------------------------------------------------------------ Joel W. Cannon | (724)223-6146 Dept. of Physics | Washington and Jefferson College | Washington, PA 15301 |

**Follow-Ups**:**Re: Finding lengths of identical sequences in lists***From:*Maris Tonso <maris@tpu.ee>