朱莉娅:广播功能与关键字参数

问题描述

假设我们有一个复合类型:

Suppose we have a composite type:

mutable struct MyType{TF<:AbstractFloat, TI<:Integer}
a::TF
b::TF
end

我们定义一个构造函数

function MyType(a; b = 1.0)
    return MyType(a, b)
end

我可以通过a的数组广播MyType，但是如何为b进行广播?

I can broadcast MyType over an array of a's, but how can I do that for b's?

我试图做

MyType.([1.0, 2.0, 3.0]; [:b, 1.0, :b, 2.0, :b, 3.0,]) 

但是，这不起作用.

请注意，以上示例完全是人为的.实际上，我有一个复合类型，它包含许多字段，其中许多字段是使用关键字参数构造的，我只想将其中的一些更改为存储在数组中的不同值.

Note that the above example is totally artificial. In reality, I have a composite type that takes in many fields, many of which are constructed using keyword arguments, and I only want to change a few of them into different values stored in an array.

推荐答案

我认为您不能使用点符号来完成此操作，但是，您可以手动构建广播呼叫:

I don't think you can do this with dot-notation, however, you can manually construct the broadcast call:

julia> struct Foo
           a::Int
           b::Int
           Foo(a; b = 1) = new(a, b)
       end

julia> broadcast((x, y) -> Foo(x, b = y), [1,2,3], [4,5,6])
3-element Array{Foo,1}:
 Foo(1, 4)
 Foo(2, 5)
 Foo(3, 6)

julia> broadcast((x, y) -> Foo(x; y), [1,2,3], [:b=>4,:b=>5,:b=>6])
3-element Array{Foo,1}:
 Foo(1, 4)
 Foo(2, 5)
 Foo(3, 6)

这篇关于朱莉娅:广播功能与关键字参数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！