Re: Distribute one list element over another
- To: mathgroup at smc.vnet.net
- Subject: [mg130485] Re: Distribute one list element over another
- From: Peter Pein <petsie at dordos.net>
- Date: Mon, 15 Apr 2013 02:29:18 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- Delivered-to: l-mathgroup@wolfram.com
- Delivered-to: mathgroup-newout@smc.vnet.net
- Delivered-to: mathgroup-newsend@smc.vnet.net
- References: <kkctn0$7fc$1@smc.vnet.net>
Am 14.04.2013 02:36, schrieb Timm Reinisch:
> Hallo,
>
> It's difficult to explain what I want to achieve and maybe if I could
> describe it better I would have been able to google a solution.
>
> My problem deals with lists of lists of the form {a1, a2, a3, {m1, m2,
> m3, m4}}
>
> e.g.
>
> data =
> {
> {a1, a2, a3, {m1, m2, m3, m4}},
> {b1, b2, b3, {n1, n2, n3, n4}},
> {c1, c2, c3, {o1, o2, o3, o4}},
> {d1, d2, d3, {p1, p2, p3, p4}},
> }
>
> I want is to go over the list and transform each of the sublists {a1,
> a2, a3, {m1, m2, m3, m4}} into a list consisting of pairs {{a1, m1},
> {a1, m2}, {a1, m3}, {a1, m4}}
> so that for the list given above I get
>
> {
> {{a1, m1}, {a1, m2}, {a1, m3}, {a1, m4}},
> {{b1, n1}, {b1, n2}, {b1, n3}, {b1, n4}},
> {{c1, o1}, {c1, o2}, {c1, o3}, {c1, o4}},
> {{d1, p1}, {d1, p2}, {d1, p3}, {d1, p4}},
> }
>
> I think it could be possible to do this using two nested map operations
> /@, but I don't find out how to do so exactly, because I run into
> trouble with the scope of the #
>
> What I'm doing at the moment is that I use a module:
>
> verteilen[liste_] := Module[{},
> {#[[1]], liste[[1]]} & /@ liste[[4]]
> ]
>
> and map it over the list I want to transform:
>
> verteilen[#] & /@ data
>
> I'm searching for a much mor elegant way to achive this transformation,
> any hints?
>
> Thanks and best regards
>
> Timm
>
>
Hi Timm,
how about Thread[#[[{1, -1}]]] & /@ data ?
Peter