Combine three lists in one with each other

Question

I have a question about combining lists, I really tried it, but that's so hard for me. I'm a newbie.

I have this kind of a list:

a={{{2,3},{1,2},{3,5}},{{1,9},{1,5},{1,7}},{{10,10},{10,10},{20,20}}}

I need this kind of result:

res={{{2,3},{1,2},{3,5},{10,10},{20}},{{1,9},{1,5},{1,7},{10,10},{20}}}

My list can have 1000 of elements...

I would be thankful for your help

Can you clarify what you want to achieve? For example, which of the input's 10s end up where in the desired output? Why should the {10,10},{20} in the output (twice) be grouped like that? — Jules Lamers, Aug 22 '17 at 16:42
These are 3 lists, which i already combine:
a1= {{2,3},{1,2},{3,5}},{{1,9},{1,5},{1,7}} a2={{10,10},{10,10}} a3={{20,20}} — Mudy Fa, Aug 22 '17 at 16:49
What should happen if the 'third list' were {{10,11},{12,13},{20,21}} rather than {{10,10},{10,10},{20,20}}? — jjc385, Aug 22 '17 at 16:52
@MudyFa But your a1 is not a list (missing {}s?), and your question does not involve a2 and a3 but rather a2~Join~a3... Could you be a bit more precise? — Jules Lamers, Aug 22 '17 at 16:53
@jjc385 this doesnt matter... its only importan to combine them in the right direction — Mudy Fa, Aug 22 '17 at 16:54
I'm asking you to clarify what the output should be if the 'third list' were {{10,11},{12,13},{20,21}} rather than {{10,10},{10,10},{20,20}}. As you've described it, it's unclear what should happen. If you're not interested in that case, then how about {{10,10},{15,15},{20,20}}? It's just not clear enough from the question (at least to me) what should happen in these cases. — jjc385, Aug 22 '17 at 16:59

score 3 · Accepted Answer · answered Aug 22 '17 at 17:43

3

If I assume some typos in your presentation, this seems to be another question about how to append columns.

a1 = {{{2, 3}, {1, 2}, {3, 5}}, {{1, 9}, {1, 5}, {1, 7}}};
a2 = {{10, 10}, {10, 10}};
a3 = {{20}, {20}};
Fold[MapThread[Append, {#1, #2}] &, {a1, a2, a3}] (* appends all*)
% // MatrixForm  (* display nicely *)

answered Aug 22 '17 at 17:43

Alan

13,686
19
38

Dont work, theres one coma mistake – Mudy Fa Aug 22 '17 at 17:54
@MudyFa Please copy the entire code. It runs fine and produces your desired output. Note that my a3 is a correction of what you wrote: you said there were missing braces, so I added the braces needed for the format to make sense. – Alan Aug 22 '17 at 18:29
No i Mean, there is a mistake in Fold, just try it!! – Mudy Fa Aug 23 '17 at 12:48
@MudyFa You must have copied it wrong. It works as it should. If you are copying and pasting, that will sometimes lose end-of-lines. But the code is good. – Alan Aug 23 '17 at 13:23
oh yes, it works, but there is something between, } and ] in the End of the Fold line something like this "^" – Mudy Fa Aug 23 '17 at 13:38
@MudyFa Odd, I see nothing of the sort, and I certainly pasted nothing of the sort. Do you actually see this in your browser? What browser are you using? – Alan Aug 23 '17 at 15:20
version 9.0... hm i dont know – Mudy Fa Aug 23 '17 at 15:42
but what is , when i have a={{1,2},{2,1}} and b ={{1,3},{4,1}}
my result with MapThread[Append[#1,#2]&,{a,b}] is :

{{1,2,{1,3}},{2,1,{4,1}}} ?? i need :

{{{1,2},{1,3}},{{2,1},{4,1}}} ... i dont get this... the position is right but but the clamp not... can u help again please?
– Mudy Fa Aug 23 '17 at 16:42
@MudyFa That is a very different question, because now a and b are matrices whereas your a1 was a list of matrices. I would write your new problem as Transpose[{a, b}]. – Alan Aug 23 '17 at 23:22

score 2 · Answer 2 · answered Jan 14 '24 at 00:14

a = {{{2, 3}, {1, 2}, {3, 5}}, {{1, 9}, {1, 5}, {1, 7}}};
b = {{10, 10}, {10, 10}};
c = {{20}, {20}};

Another possibility

MapThread[Join[#1, {#2}, {#3}] &, {a, b, c}]

{{{2, 3}, {1, 2}, {3, 5}, {10, 10}, {20}}, {{1, 9}, {1, 5}, {1, 7}, {10, 10}, {20}}}

score 1 · Answer 3 · answered Jan 14 '24 at 04:58

I have changed a few entries to visually differentiate where the items are landing after various operations. Matrix dimensions, however, remain the same as those from the accepted answer.

a = {{{2, 3}, {1, 2}, {3, 5}}, {{1, 9}, {1, 5}, {1, 7}}};
b = {{10, 20}, {30, 40}};
c = {{25}, {35}};
g1 = MapThread[Join@## &, {a, List /@ b, List /@ c}];
g2 = MapThread[Join, {a, List /@ b, List /@ c}];
g3 = MapThread[Catenate@{##} &, {a, List /@ b, List /@ c}];
g1 == g2 == g3

(* True *)

Result:

MatrixForm /@ {a, b, c, g1}

score 1 · Answer 4 · answered Jan 14 '24 at 17:09

a = {{{2, 3}, {1, 2}, {3, 5}}, {{1, 9}, {1, 5}, {1, 7}}};
b = {{10, 10}, {10, 10}};
c = {{20}, {20}};

Using Thread and ReplaceAll:

ReplaceAll[m_?MatrixQ :> Splice@m][Thread[{a, b, c}]]
({{{2, 3}, {1, 2}, {3, 5}, {10, 10}, {20}}, {{1, 9}, {1, 5}, {1, 7}, {10, 10}, {20}}})

Combine three lists in one with each other

4 Answers4