从Julia中的数组中采样行 [英] Sample rows from an array in Julia
本文介绍了从Julia中的数组中采样行的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我可以从一维数组中采样.例如
I can sample from a 1-D array just fine. E.g.
julia> a = [1; 2; 3]
3-element Array{Int64,1}:
1
2
3
julia> sample(a, myweights, 5)
5-element Array{Int64,1}:
1
2
1
3
3
我也可以采集加权样本:
I can also take weighted samples:
julia> myweights = weights([0.8, 0.1, 0.1])
StatsBase.WeightVec{Float64,Array{Float64,1}}([0.8,0.1,0.1],1.0)
julia> sample(a, myweights, 5)
5-element Array{Int64,1}:
2
1
1
1
1
我想对2D数组执行相同的操作,但是按行而不是按元素进行采样.例如.如果我有数组
I'd like to do the same thing for a 2D array, but sampling by row and not by element. E.g. if I have the array
julia> b = [1 1 1; 2 2 2; 3 3 3]
3×3 Array{Int64,2}:
1 1 1
2 2 2
3 3 3
我希望能够获取未加权和加权的样本,这些样本可以为我提供类似的输出
I'd like to be able to take unweighted and weighted samples that give me outputs like
1 1 1
2 2 2
1 1 1
1 1 1
3 3 3
我该怎么做?
推荐答案
这里最简单的解决方案是从行的索引中采样,然后使用它来索引矩阵:
The simplest solution here is to sample from the indices of the rows, and then use that to index into your matrix:
julia> idxs = sample(indices(b, 1), myweights, 10)
10-element Array{Int64,1}:
1
1
1
2
1
1
3
1
1
1
julia> b[idxs, :]
10×3 Array{Int64,2}:
1 1 1
1 1 1
1 1 1
2 2 2
1 1 1
1 1 1
3 3 3
1 1 1
1 1 1
1 1 1
这篇关于从Julia中的数组中采样行的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文