Re: SortBy
- To: mathgroup at smc.vnet.net
- Subject: [mg118191] Re: SortBy
- From: Eric Brown <eric.c.brown at mac.com>
- Date: Sat, 16 Apr 2011 07:32:55 -0400 (EDT)
I think that it takes the head of some function:
KS={{300,48,2},{500,23,5},{120,55,7},{40,32,1}};
(* define a new function *)
secondElement[x_]:=x[[2]]
SortBy[KS,secondElement]
Out[17]= {{500,23,5},{40,32,1},{300,48,2},{120,55,7}}
Or even a pure function:
SortBy[KS, (#[[2]]&)]
Out[18]= {{500,23,5},{40,32,1},{300,48,2},{120,55,7}}
SortBy[KS, (Part[#,2]&)]
Out[19]= {{500,23,5},{40,32,1},{300,48,2},{120,55,7}}