Re: pure functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg23299] Re: [mg23237] pure functions*From*: BobHanlon at aol.com*Date*: Sun, 30 Apr 2000 21:13:49 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

exli = {{1, 2}, {3, 4}, {5, 6}, {7, 8}}; (#[[1]] + #[[2]]) & /@ exli {3, 7, 11, 15} ((Plus @@ #) & /@ exli) {3, 7, 11, 15} m = Array[x, {3, 3}]; (#[[1]] + #[[2]] + #[[3]]) & /@ m {x[1, 1] + x[1, 2] + x[1, 3], x[2, 1] + x[2, 2] + x[2, 3], x[3, 1] + x[3, 2] + x[3, 3]} ((Plus @@ #) & /@ m) {x[1, 1] + x[1, 2] + x[1, 3], x[2, 1] + x[2, 2] + x[2, 3], x[3, 1] + x[3, 2] + x[3, 3]} In a message dated 4/29/2000 10:35:57 PM, helgea at inoc.chalmers.se writes: >Of all the nice functions such as Map, Mapall, Thread, Apply .... I have >not been able to write a simple code to generate the following >procedure. > >I have a two dimensional list like > >li={{11,12,13,..},{21,22,23,...},{31,32,33,..},...} > >Since i like to use the pure function command I would like to map my >pure function with arguments #1,#2,#3,.... on all the sublists in li. > >Let me exemplify with a simple pure function that add to numbers. >(#1+#2)& > >if exli={{1,2},{3,4},{5,6},{7,8}} > >then I want to get the result >{3,7,11,15} > >One solution, but not allways suitable for me, is the following > >(#1+#2)&[Sequence @@ Transpose[exli]]. > >I want to get rid of the Transpose command and if possible also making >use of the /@ notation for Map. Since I have seen so many elegant >examples in the mailing lists I hope I can get something out of this. > Bob BobHanlon at aol.com