Take a lineout of a matrix, defined by a function

2 次查看（过去 30 天）
Noah Chrein
Noah Chrein 2015-7-6
评论： Noah Chrein 2015-7-6
Let M be an m by n matrix, let f:(1:m)->(1:n)
how can I create a vector that contains all the points that f hits?
Example:
Let:
M = [1 2 3;
4 5 6;
7 8 9]
and let j = f(i) = i
that is, my output vector should be v = [1 5 9]
or let j = f(i) = 4-i
in this case, v = [7 5 3]
or, more complicated, let j = f(i) = round(1+sqrt(i))
then v = [4 5 9]

请先登录，再回答此问题。

采纳的回答

Thorsten
Thorsten 2015-7-6
编辑：Thorsten 2015-7-6
i = 1:size(M,1);
f = @(i) i;
M(sub2ind(size(M), i, f(i)))
f = @(i) 4 - i;
M(sub2ind(size(M), i, f(i)))
f = @(i) round(1+sqrt(i));
M(sub2ind(size(M), i, f(i)))

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Creating and Concatenating Matrices 的更多信息

标签

产品

Community Treasure Hunt

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

Start Hunting!

Translated by