Re: split the sublists into parts according to some rules

*To*: mathgroup at smc.vnet.net*Subject*: [mg127936] Re: split the sublists into parts according to some rules*From*: Dana DeLouis <dana01 at me.com>*Date*: Mon, 3 Sep 2012 02:56:30 -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

Hi. I see you have an excellent solution. I'm not sure, but would you want the function to work on a vector as well? splitToParts[{a,b,c,d,e,f,g},2] {} This is not any better, but takes a different approach. If one had 12 items, and wanted to group them into 5 groups, the size of each group might be: k=IntegerPartitions[12,{5}] //Last {3,3,2,2,2} We note that the first 2 items are 1 larger then rest, the count being.. Mod[12,5] 2 For the right-side group, we adjust the starting position of Partition, and don't allow overhang of the right. SplitToParts[list_List,n_Integer?Positive]:=Module[ {v,Fx}, (* Custom Function *) Fx[v_List,x_Integer?Positive]:=Module[ {k=Length[v], left, right}, If[x==1,Return[v]]; If[x==k,Return[List/@v]]; {m,p}=QuotientRemainder[k,x]; If[p==0, Partition[v,k/x], (* Else *) left = Partition[v,m+1][[;;p]]; right = Partition[v,m,m,{-p,-1}][[p-x;;]]; Join[left,right] ] ]; (* If it's a vector.. *) If[Depth[list]==2, If[Length[list]<n,Return[{}],Return[Fx[list,n]]]]; (* Else it's a list *) v=Select[list,Length[#]>=n&]; If[Length[v]==0,Return[{}] ]; Map[Fx[#,n]&,v] ] // End of Function ============ Some test data: v={{a,b,c,d,e},{x,y,z},{a1,a2,a3,a4}}; SplitToParts[v,3] {{{a,b},{c,d},{e}}, {{x},{y},{z}}, {{a1,a2},{a3},{a4}}} SplitToParts[v,4] {{{a,b},{c},{d},{e}}, {{a1},{a2},{a3},{a4}}} SplitToParts[v,5] {{{a},{b},{c},{d},{e}}} SplitToParts[v,6] {} Appears to work with a vector: v={a,b,c,d,e}; SplitToParts[v,3] {{a,b},{c,d},{e}} SplitToParts[v,4] {{a,b},{c},{d},{e}} SplitToParts[v,6] {} = = = = = = = = = = HTH :>) Dana DeLouis Mac & Mathematica 8 = = = = = = = = = = On Friday, August 31, 2012 4:01:50 AM UTC-4, Joug Raw wrote: > Dear all, > > > > I have a long list which has many sublists inside, > > > > Thelonglist={{a,b,c,d,e},{x,y,z},{a1,a2,a3,a4},...} > > > > Each sublist has length > 1(no single element sublist exists) . And the > > lengths of the sublists are different and unknow in advanced. The length of > > some of the sublists are odd number, such as {a,b,c,d,e} and {x,y,z}. Some > > sublists have even number list length, like {a1,a2,a3,a4}. > > > > What I want to achieved is to split each sublist into two (or three, or > > more) parts. In the two parts case, if the length of original sublist is > > even number, the two new parts will have same length, e.g, {a1,a2,a3,a4} > > become {{a1,a2},{a3,a4}}. If the sublist has length in odd number, > > after splitting one of the two parts should have one more element than the > > other. > > > > That is, > > Input: Thelonglist={{a,b,c,d,e}, {x,y,z}, {a1,a2,a3,a4},...} > > Output: Newlist={{a,b,c}, {d,e}}, {{x,y}, {z}}, {{a1,a2}, {a3,a4}},...} > > > > Or the same idea for the three parts case, > > Input: Thelonglist={{a,b,c,d,e}, {x,y,z}, {a1,a2,a3,a4},...} > > Output: Newlist={{{a,b}, {c,d}, {e}}, {{x},{y},{z}}, {{a1}, {a2}, > > {a3,a4}}, ...} > > > > For the case of 4 parts, the number 4 is larger than the length of some > > sublists and I will abandon those list with short length. > > Input: Thelonglist={{a,b,c,d,e}, {x,y,z}, {a1,a2,a3,a4},...} > > Output: Newlist={{{a}, {b}, {c}, {d,e}}, {{a1}, {a2}, {a3}, {a4}}, ...} > > > > Could there be a simple function to achieve this idea generally? Say, a > > function like *SplittoPart[**list_*, *partnumber_**]*, in which I just need > > to give the input list and the number of parts of sublists I want to have. > > Then it will do the job above. If the number of sublist is larger then the > > length of some sublists, the function just abandon those short list and do > > the split(or partition) work on the other lists with long enough length. > > Could some one help me on this? > > > > If that is too complicated, I would still be happy to see some one could > > give me a solution only for the case of splitting to two parts, > > > > Input: Thelonglist={{a,b,c,d,e}, {x,y,z}, {a1,a2,a3,a4},...} > > Output: Newlist={{a,b,c}, {d,e}}, {{x,y}, {z}}, {{a1,a2}, {a3,a4}},...} > > > > Thanks a lot for your kind help!

**Follow-Ups**:**Re: split the sublists into parts according to some rules***From:*Bob Hanlon <hanlonr357@gmail.com>

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**Re: split the sublists into parts according to some rules**

**Re: split the sublists into parts according to some rules**