Adding each row to previous row in a vector-Not Cumulative
3 ビュー (過去 30 日間)
古いコメントを表示
Hi , I've looked everywhere to find the solution for this but I couldn't find the answer. Here 's the problem. How to add each row in a vector with just the previous row? For example here is the process on this vector: A=[2 1 7 9 4] and the answer should be this vector: C=[3 8 16 13]
Thanks in advance.
0 件のコメント
採用された回答
Sukuchha
2011 年 7 月 20 日
A=[2 1 7 9 4]; B = A(1:end-1)+diff(cumsum(A));
1 件のコメント
Jan
2011 年 7 月 20 日
diff(cumsum(A)) ?! An expensive method to get: A(2:end). But in addition there is the danger of rounding errors, e.g. diff(cumsum([1e16, 1, 5])) is [0, 4] ! Therefore I strongly recommend not to use this.
その他の回答 (3 件)
Jan
2011 年 7 月 20 日
Easier and faster:
B = A(1:end-1) + A(2:end)
2 件のコメント
Sukuchha
2011 年 7 月 21 日
Jan, your method is better ! i feel like stupid now ! I need to remember always solve problems in a simplier way !
Jan
2011 年 7 月 21 日
@Sukuchha: Often a direct translation of the human language is helpful. You've formulated your algorithm very clear already: "add each row in a vector with just the previous row". So you did solve the biggest part of the problem already. Most of the questions in this forum are much less clear.
Paulo Silva
2011 年 7 月 20 日
C=arrayfun(@(x)plus(A(x),A(x-1)),2:numel(A))
or with a for loop
C=zeros(1,size(A,2)-1);
for x=2:size(A,2)
C(x-1)=A(x)+A(x-1);
end
C
0 件のコメント
参考
カテゴリ
Help Center および File Exchange で Subplots についてさらに検索
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!