RE: How Do You Reduce Multiple Elements in a List?

*To*: mathgroup at smc.vnet.net*Subject*: [mg33883] RE: [mg33863] How Do You Reduce Multiple Elements in a List?*From*: "DrBob" <majort at cox-internet.com>*Date*: Sun, 21 Apr 2002 06:12:36 -0400 (EDT)*Reply-to*: <drbob at bigfoot.com>*Sender*: owner-wri-mathgroup at wolfram.com

Frequencies in the DataManipulation package will do that for you. Bobby -----Original Message----- From: Bob Harris [mailto:nitlion at mindspring.com] To: mathgroup at smc.vnet.net Subject: [mg33883] [mg33863] How Do You Reduce Multiple Elements in a List? 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