朱莉娅多维数组类型? [英] Julia multidimensional array types?

问题描述

我有一个类型为Array{Float64,2}的数组，但是它是1列的数组，因此我无法将其传递给期望类型为Array{Float64,1}的单列数组的函数.我真的不了解2的含义或如何解决我的问题，而且我也无法通过搜索任何文档来弄清问题.

解决方案

在Array{Float64,2}中，2是数组中的维数.由于您说的是它是由1列组成的数组"，因此您可能具有二维的内容，其中包含一行或一列，即其中一个

julia> c = rand(1,3)
1x3 Array{Float64,2}:
 0.190944  0.928697  0.251519

julia> d = rand(3,1)
3x1 Array{Float64,2}:
 0.0818493
 0.0342291
 0.58341  

要将其转换为一维数组，可以手动切片该数组或使用 解决方案

In Array{Float64,2}, the 2 is the number of dimensions in the array. Since you say it's "it's an array of 1 column", you probably have something which is 2-dimensional with either one row or one column, i.e. one of

julia> c = rand(1,3)
1x3 Array{Float64,2}:
 0.190944  0.928697  0.251519

julia> d = rand(3,1)
3x1 Array{Float64,2}:
 0.0818493
 0.0342291
 0.58341  

To turn this into a 1-dimensional array, you could slice the array manually or use squeeze, as you prefer:

julia> c[1,:]
3-element Array{Float64,1}:
 0.190944
 0.928697
 0.251519

julia> squeeze(d,2)
3-element Array{Float64,1}:
 0.0818493
 0.0342291
 0.58341  

Either approach should give you something of type Array{Float64,1}.

---

As noted in the comments, another approach is to use reshape, e.g. (using a different random c):

julia> reshape(c, length(c))
3-element Array{Float64,1}:
 0.680653 
 0.0573147
 0.607054 

This has the advantage -- and disadvantage -- of not caring whether you have an array of shape 1xN or Nx1.

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