R填充向量 [英] R populating a vector

问题描述

我的矢量为零，长度为10.所以

I have a vector of zeros, say of length 10. So

v = rep(0,10)

我要基于v1中的一组索引和实际上具有顺序值的另一个矢量v2填充矢量的某些值.所以另一个向量v1的索引是

I want to populate some values of the vector, on the basis of a set of indexes in v1 and another vector v2 that actually has the values in sequence. So another vector v1 has the indexes say

v1 = c(1,2,3,7,8,9)

和

v2 = c(0.1,0.3,0.4,0.5,0.1,0.9)

最后我想要

v = c(0.1,0.3,0.4,0,0,0,0.5,0.1,0.9,0)

因此v1中的索引是从v2映射的，其余索引为0.我显然可以编写一个for循环，但是由于实际矩阵的长度，这在R中花费的时间太长.有任何简单的方法可以做到这一点吗?

So the indexes in v1 got mapped from v2 and the remaining ones were 0. I can obviously write a for loop but thats taking too long in R, owing to the length of the actual matrices. Any simple way to do this?

推荐答案

您可以通过以下方式进行分配:

You can assign it this way:

v[v1] = v2

例如:

> v = rep(0,10)
> v1 = c(1,2,3,7,8,9)
> v2 = c(0.1,0.3,0.4,0.5,0.1,0.9)
> v[v1] = v2
> v
 [1] 0.1 0.3 0.4 0.0 0.0 0.0 0.5 0.1 0.9 0.0

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