您如何制作视图尺寸? [英] How do you make a view drop dimensions?

问题描述

在v0.5-rc0上的一个简单示例可以很好地说明这一点:

This is best illustrated by a simple example on v0.5-rc0:

julia> view(zeros(4,2),:,2)
4-element SubArray{Float64,1,Array{Float64,2},Tuple{Colon,Int64},true}:
 0.0
 0.0
 0.0
 0.0

julia> zeros(4,2)[:,2]
4-element Array{Float64,1}:
 0.0
 0.0
 0.0
 0.0

第一个返回只有一个列的Array{Float64,2}的子数组，但是v0.5删除尺寸.有没有办法使SubArray/View删除未使用的尺寸?

The first returns a SubArray of Array{Float64,2} with only 1 column, but v0.5 drops dimensions. Is there a way to make the SubArray/View drop the unused dimension?

推荐答案

正如Tasos所述，它是 和Array{Float64, 2}的视图，但是视图本身已经是一维的.实际上，

As Tasos mentioned, it's a view of an Array{Float64, 2}, but the view itself is one-dimensional already. In fact,

julia> T = SubArray{Float64,1,Array{Float64,2},Tuple{Colon,Int64},true};
julia> T <: AbstractVector{Float64}
true

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