Re: Map onto a column

*To*: mathgroup at smc.vnet.net*Subject*: [mg125463] Re: Map onto a column*From*: Sseziwa Mukasa <mukasa at gmail.com>*Date*: Wed, 14 Mar 2012 00:44:57 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <201203130802.DAA12753@smc.vnet.net>

Transpose the matrix and MapAt the appropriate row then Transpose back: Transpose[MapAt[f,Transpose[a],2]] On Mar 13, 2012, at 4:02 AM, Sly Pandemia wrote: > Is there a neat way to map a function onto a specific column in an > array? > > For example if I have > > a = {{1,2,3},{4,5,6},{7,8,9}} > > and I want to map f onto the second element in each row. I would > normally use > > b = Map[MapAt[f,#,2]&,a] > > but this seems a bit awkward. I would expect to be able to use > > b = MapAt[f,a,{All,2}] > > but this appears to be illegal syntax. > > Is there any way to do what I want with a single Map/MapAt function? >

**References**:**Map onto a column***From:*Sly Pandemia <slypandemia@gmail.com>