Re: Sorting question

*To*: mathgroup at smc.vnet.net*Subject*: [mg52772] Re: Sorting question*From*: "Dr. Wolfgang Hintze" <weh at snafu.de>*Date*: Mon, 13 Dec 2004 04:22:13 -0500 (EST)*References*: <cpeko6$764$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Assuming that "out of order with" means unequal here's an approach using Select. Let your list be In[33]:= d = {{1, 1}, {2, 3}, {3, 2}, {4, 4}} Out[33]= {{1, 1}, {2, 3}, {3, 2}, {4, 4}} Then In[32]:= s = Select[d, #1[[1]] == #1[[2]] & ] Out[32]= {{1, 1}, {4, 4}} Hope this helps. Wolfgang "out of order with" Nimrod wrote: > A simple sorting question that has me stumped as to how to do it both > quickly and elegantly. > > I have a list of data pairs of the form (distance, time). I want to > sort on the distance element and then remove all pairs where the time > element is out of order with the distance element. For example > ((1,1),(2,3),(3,2),(4,4)) --> ((1,1),(4,4)). The actual lists are > much longer. > > Thanks in advnace, > > Nimrod. > >