Re: Selecting Sub-lists After Split

*To*: mathgroup at smc.vnet.net*Subject*: [mg77466] Re: Selecting Sub-lists After Split*From*: Bill Rowe <readnewsciv at sbcglobal.net>*Date*: Sat, 9 Jun 2007 05:38:12 -0400 (EDT)

On 6/8/07 at 5:34 AM, gregory.lypny at videotron.ca (Gregory Lypny) wrote: >Suppose I have a list of real number called myList. I split it into >sub-lists of positive and negative numbers called myNewList by doing >this (there may be a more elegant way): >myNewList = Split[myList, #1 #2 > 0 &] >Now, how can I select all of the sub-lists of negative numbers from >myNewList? A simple way to do this would be to use pattern matching and Cases. =46irst generate so data In[12]:= data = Split[RandomReal[{-1, 1}, 20], #1 #2 > 0 &] Out[12]= {{0.515309},{-0.014795},{0.329838,0.896598},{-0.414435, -0.326671,-0.347789,-0.627698,-0.763855,-0.85736,-0.774624},{0.861427, 0.387308,0.590255},{-0.502033},{0.813789},{-0.748274,-0.297541, -0.170911,-0.948834}} then to pick out the sub-lists with negative values In[13]:= Cases[data, {_?(# < 0 &), ___}] Out[13]= {{-0.014795},{-0.414435,-0.326671,-0.347789,-0.627698, -0.763855,-0.85736,-0.774624},{-0.502033},{-0.748274,-0.297541,-0.170911, -0.948834}} -- To reply via email subtract one hundred and four