Re: Sort List of Lists

*To*: mathgroup at smc.vnet.net*Subject*: [mg24820] Re: [mg24809] Sort List of Lists*From*: "Richard Finley" <rfinley at medicine.umsmed.edu>*Date*: Sun, 13 Aug 2000 23:49:44 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Dana, If the 2nd elements are numeric, you can use: Sort[list, (#2[[2]] > #1[[2]]) &] but be careful....this won't work if the second elements are not numeric, eg. list = {{4,c},{2,d},{7,a}} In that case you could use the following which is more general and will work in either case: Sort[list, (Order[#1[[2]], #2[[2]]] == 1) &] Basically, the second argument to the Sort function is an order function that defines the order of elements by a Boolean function. regards, RF >>> "dana2" <dan_news at hotmail.com> 08/13/00 01:16AM >>> Hello. Could someone please give me a clue on how to sort a list based on the Second Element in a List: I think one needs to use a "pure function" but I am too new with Mathematica (v4) (Trying to learn though) :>) For Example, I would like to sort this list based on the second element in each sub-list in "Descending" order: {{9, 2}, {1, 6}, {2, 4}} Results would be: { {1,6},{2,4},{9,2} } I think I will learn a lot about Lists, Sorting, and Pure Functions all in one shot if I could get a hint on how to do this. Thank you very much. Dana