问题描述
我有一个矩阵，例如
A = [ 1 2 3; 4 5 6; 7 8 9] ;
和一个大小为1x3的向量，它指定每行中哪个元素是我要查找的元素 - 即如果
and a vector of size 1x3 which specifies which element in each row is the one I'm looking for - i.e. If
vector = [ 1 2 1 ]
然后所需的输出是
[ 1 5 7 ]
因为 1 是1中的第1个元素'st row， 5 是第2行中的2'，而 7 是第1行第3行中的元素。
since 1 is the 1'st element in the 1'st row, 5 is the 2'nd in the 2'nd row, and 7 is the 1'st element in the 3'rd row.
我如何实现这一目标？无法找到内置函数来做到这一点，这让我感到惊讶。
How do I achieve this? Couldn't find a built in function to do this, which surprised me.
推荐答案
首先，Matlab中的索引去了从上到下。
所以在你的情况下 A [1] = 1，A [2] = 4，A [3] = 7
First of all, the indexes in Matlab go from top to bottom.
So in your case A[1] = 1 , A[2] = 4 , A[3] = 7
也就是说，在A'上工作会更容易，因为它有点琐碎。
That said, it would be easier to work on A' , because its a bit more trivial.
B = A';
B((vector + [0:2].* 3))
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