group sum with matrix

7 次查看（过去 30 天）
Boram Lim
Boram Lim 2018-5-1
评论： Boram Lim 2018-5-1
With below matrix, I would like to have a sum of the third column and a sum of the fourth column by groups that are the combination of the first and second column.
1 1 1 0.5
1 1 2 0.5
1 1 3 0.5
1 1 4 0.5
1 1 5 0.5
1 2 6 0.5
1 2 7 0.5
1 2 8 0.5
1 2 8 0.5
1 2 9 0.5
2 1 0.1 2
2 1 0.2 2
2 1 0.3 2
2 1 0.4 2
2 1 0.5 2
2 2 0.6 2
2 2 0.7 2
2 2 0.8 2
2 2 0.8 2
2 2 0.9 2
So, here is what I am desiring for
1 1 15 2.5
1 2 38 2.5
2 1 1.5 10
2 2 3.8 10
  1 个评论
Guillaume
Guillaume 2018-5-1
This is very similar to the question you asked yesterday. The same method can be used for both, so please read and learn from the answers you're given as otherwise people will start ignoring your questions.

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Ameer Hamza
Ameer Hamza 2018-5-1
The following code will summarise the table as described in question
groups = findgroups(A(:, 1), A(:, 2));
[~, uniqueGroupsIndex] = unique(groups);
uniqueGroups = A(uniqueGroupsIndex, 1:2);
s1 = splitapply(@(x) sum(x), A(:, 3:end), findgroups(A(:, 1), A(:, 2)) );
final = [uniqueGroups s1];
  4 个评论
显示 2更早的评论
Boram Lim
Boram Lim 2018-5-1
@Guillaume Thank you. I was trying to use accumarray for this but it did not work. I did not know the slpitapply. Btw, for S1, If I want to have the output with same number row with original data A. How I should do it? When I tried
s1(groups)
It does not work. Thank you in advance.
Boram Lim
Boram Lim 2018-5-1
I got it. It was pretty simple. Thank you.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Structures 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by