Re: List processing

*To*: mathgroup at smc.vnet.net*Subject*: [mg37249] Re: List processing*From*: "Carl K. Woll" <carlw at u.washington.edu>*Date*: Fri, 18 Oct 2002 05:17:36 -0400 (EDT)*Organization*: University of Washington*References*: <aokbp7$afv$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi John, I remember there being a similar thread on this subject a while ago, but I am too lazy to check it out. The simplest solution seems to be using Interval, although it may not be very fast. For example In[3]:= Interval[{100,200},{150,250},{120,270},{300,400}] Out[3]= Interval[{100, 270}, {300, 400}] If the above is not sufficiently fast for you, then you may want to search the archives for the thread I mentioned above. Carl Woll Physics Dept U of Washington "John Leary" <leary at paradise.net.nz> wrote in message news:aokbp7$afv$1 at smc.vnet.net... > Greetings > > This problem can be solved by conventional programming, but I wonder if > there is an elegant Mathematica solution ? > > A list contains pairs of values, with each pair representing the lower and > upper edge of a sub-range. Some of the sub-ranges partially overlap, some > fully overlap, others don't overlap at all. The problem is to produce a > second list that contains the overall upper and lower edges of the > overlapping sub-ranges. > > A simple example : {{100,200},{150,250},{120,270},{300,400}} would result > in {{100,270},{300,400}}. > > In the real case, the input list has several hundred elements and the > output list typically has five elements. > > I have a working solution based on loops, but there must be a more elegant > one. I would be very grateful for any suggestions. > > > Best regards > > John Leary > >