Multiplying values in one column with values in another, depending on criteria

1 次查看（过去 30 天）

显示更早的评论

Ulrik Nash 2011-5-17

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/7578-multiplying-values-in-one-column-with-values-in-another-depending-on-criteria

采纳的回答： Teja Muppirala

Hi Everyone,

Suppose I have the following matrix:

A =

1.0__0.7__4.4__0.9__50.9

3.0__0.8__5.2__1.0__28.7

6.0__0.5__3.2__0.7__10.5

7.0__-0.5__3.6__0.8__87.7

Now I wish to calculate a value, which is found as follows:

1. Multiply the values in column 2, with the corresponding values in column 5, where the corresponding value in column 4 is greater than or equal to 0.8.

2. Sum the values found in step 1.

So, the answer I am looking for is:

0.7*50.9 + 0.8*28.7 + -0.5*87.7 = 14.74

What expression might do this?

Regards,

Ulrik

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Teja Muppirala 2011-5-17

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/7578-multiplying-values-in-one-column-with-values-in-another-depending-on-criteria#answer_10437

在 MATLAB Online 中打开

One way to do it:

sum( A(:,2) .* A(:,5) .* (A(:,4) >= 0.8) )

2 个评论
显示无隐藏无

Teja Muppirala 2011-5-17

Another possibility,

idx = A(:,4) >= 0.8;

sum( A(idx,2) .* A(idx,5) )

Ulrik Nash 2011-5-17

Thank you very much for the swift reply, Teja!

请先登录，再进行评论。

类别

MATLAB Mathematics

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

Community Treasure Hunt

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

Start Hunting!

Translated by