Adding elements in the sublists

Question

How can I add the elements in the sublists?
For example, if I have the list which is

 m={{1,3},{2,3},{4,1}}

then, the output that I want is 3+3+1=10. How can I do this?

You can use Part to get the elements from the list, then Total to sum them up. — b.gates.you.know.what, Oct 30 '12 at 09:44
Plus @@@ (m\[Transpose]) will give you a list of the sums of the various elements of your list. — image_doctor, Oct 30 '12 at 10:00
Total[m[[All, 2]]] adds up the second column of m. Replace 2 with 1 to get the first column. Look up Part. — Cameron Murray, Oct 30 '12 at 10:02
@Sungjin Lee Welcome to Mathematica.SE! I suggest the following: 1) As you receive help, try to give it too, by answering questions in your area of expertise. 2) Read the FAQs! 3) When you see good Q&A, vote them up by clicking the gray triangles, because the credibility of the system is based on the reputation gained by users sharing their knowledge. ALSO, remember to accept the answer, if any, that solves your problem, by clicking the checkmark sign` — chris, Oct 30 '12 at 10:26
@Mr.Wizard, I suppose so, yes. Still, it's poor form not to explicitly indicate the base! ;) — J. M.'s missing motivation, Oct 30 '12 at 11:03

score 4 · Answer 1 · edited Apr 13 '17 at 12:56

4

I thinks the cleanest way is:

Total@m[[All, 2]]

using Esc[[Esc and Esc]]Esc.

If you use it a lot (like me), you can create shortcuts as explained here.

edited Apr 13 '17 at 12:56

Community

answered Oct 30 '12 at 12:49

Murta

You can use these shortcuts if you don't like pressing Esc every time for Part brackets – rm -rf Oct 30 '12 at 14:27
Yes, I use it. I put in the post. Tks – Murta Oct 30 '12 at 18:46
@Murta, I asked the Q on [[ ]] but find all the answers a pain. Can you make a palette button or single front-end command? – alancalvitti Nov 13 '15 at 17:29

chris · Answer 2 · 2012-10-30T12:29:06.760

1

Following @b.gatessucks

 Total[m[[;; , 2]]]

  (* 7 *)

If you want to sum all components (as @image_doctor pointed out too, sorry I missed that)

 Plus @@@ Transpose[m]

 (* 7 7 *)

edited Oct 30 '12 at 12:29

answered Oct 30 '12 at 12:00

chris

1

Total[m[[All , 2]]] works as well. :) – J. M.'s missing motivation Oct 30 '12 at 12:05

score 0 · Answer 3 · answered Oct 30 '12 at 14:10

0

Last@Total[{{1, 3}, {2, 3}, {4, 1}}]

or

Total[{{1, 3}, {2, 3}, {4, 1}}]

for both components

answered Oct 30 '12 at 14:10

s0rce

score 0 · Answer 4 · answered Nov 13 '15 at 17:26

0

 {{1, 3}, {2, 3}, {4, 1}} // Query[Total, 2]

7

Unfortunately the current Query and associated Dataset implementation is riddled with workarounds - this is going to tech support >>

{{1, 3}, {2, 3}, {4, 1}} // Query[Total, 2] // Trace // LeafCount

3175

Anyone interested in a timing study?

answered Nov 13 '15 at 17:26

alancalvitti

{{1, 3}, {2, 3}, {4, 1}} // Query[Total, 2] // Trace // LeafCount results in 697 as of May 2023. – Syed May 12 '23 at 07:30

score 0 · Answer 5 · answered Nov 13 '15 at 18:27

0

Just For fun.

m = {{1, 3}, {2, 3}, {4, 1}}; Last[Total[m]]

answered Nov 13 '15 at 18:27

Bob Brooks

5 Answers5