Re: List Help Needed
- To: mathgroup at smc.vnet.net
- Subject: [mg68867] Re: List Help Needed
- From: albert <awnl at arcor.de>
- Date: Mon, 21 Aug 2006 06:33:23 -0400 (EDT)
- References: <ecbo4l$r5j$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Nimrod wrote:
> What combination of Map, MapAt, ...
>
> will transform {{a,b},{c,d},...} to {{a,f[b]},{c,f[d]},...}
>
> Thanks in advance.
>
> Nimrod
I think you will need a pure function that handles the first and second
entry in the lists differently. This is a possibility with Map:
In[6]:= Map[{#[[1]],f[#[[2]]]}&,{{a, b}, {c, d}}]
Out[6]= {{a, f[b]}, {c, f[d]}}
For this case, Apply results in somewhat shorter code:
In[8]:= Apply[{#1,f[#2]}&,{{a, b}, {c, d}},{1}]
Out[8]= {{a, f[b]}, {c, f[d]}}
And using the short form of Apply[,{1}] it becomes even shorter:
In[9]:= {#1,f[#2]}& @@@ {{a, b}, {c, d}}
Out[9]= {{a, f[b]}, {c, f[d]}}
hth,
albert