How Do You Reduce Multiple Elements in a List?

*To*: mathgroup at smc.vnet.net*Subject*: [mg33863] How Do You Reduce Multiple Elements in a List?*From*: Bob Harris <nitlion at mindspring.com>*Date*: Sat, 20 Apr 2002 02:49:57 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Howdy, This seems like such a simple thing, yet I've search through the big book trying to figure it out. Perhaps someone can help me... Given a list of integers that generally contains the same number many times, I'd like to reduce it to a list that just gives me the number/count pairs. For example, I'd like to convert the list {1, 1, 1, 1, 1, 2, 2, 2, 4, 4, 4, 4, 4, 4} into {{1,5}, {2,3}, (4,6}} Is there a built-in function to do this? Seems like a histogramming operation, but I get no useful matches from ?*Hist*. Thanks, Bob H

**Follow-Ups**:**Re: How Do You Reduce Multiple Elements in a List?***From:*SteveC <steve@fractalus.com>