For matrices, mean (X) is a row vector containing the mean value of each column.

对于矩阵来说，MEAN (X)是包含了每列平均值的行向量。

Then for each row from the fact table scan, the foreign key is also hashed and probed into the bit vector to determine whether the current fact table row is filtered out.

然后针对事实表扫描的每一行，外键也被散列并探测到位向量中，从而判断当前的事实表行是否被过滤掉了。

But if you wanted to create a vector to sum each row, you might be inclined to try the following.

但是，如果希望创建一个向量来求每行的总和，您可能会编写下面这样的代码。

One thing that can be confusing about R's "everything is a vector" approach is that row-wise and column-wise operations may not adhere to your intuition.

关于 R 的 “所有东西都是向量” 方式，容易引起混乱的一点是行操作和列操作可能不符合直觉。

This way 2... I could take that row times my vector.

折中方法2…我取那一行乘以我的向量。