
Re: Distribute one list element over another
Posted:
Apr 15, 2013 2:28 AM


In[1]:= 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}}}Out[1]= {{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}}} In[2]:= Table[{data[[j,1]],#}&/@Last[data[[j]]],{j,1,Length[data]}]Out[2]= {{{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}}} Tomas
> From: timm.reinisch@sprechkultur.com > Subject: Distribute one list element over another > To: mathgroup@smc.vnet.net > Date: Sat, 13 Apr 2013 20:38:35 0400 > > 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 >

