字典的矢量化索引 [英] Vectorized indexing for a dictionary

问题描述

我想在 Julia 中找到一种简洁的语法，用于以矢量化方式索引字典.在 R 中，我会执行以下操作:

I would like to find a succinct syntax in Julia for indexing a dictionary in a vectorized manner. In R, I would do the following:

dict <- c("a" = 1, "b" = 2)
keys <- c("a", "a", "b", "b", "a")
dict[keys]

在 Julia 中，如果我有这样的 dict 和 keys，

In Julia, if I have a dict and keys like this,

dict = Dict(:a => 1, :b => 2)
keys = [:a, :a, :b, :b, :a]

然后我可以使用列表理解来实现所需的结果:

then I can achieve the desired result using a list comprehension:

julia> [dict[key] for key in keys]
5-element Array{Int64,1}:
 1
 1
 2
 2
 1

有没有更简洁的向量化语法，类似于 R 语法?

Is there a more succinct vectorized syntax, similar to the R syntax?

推荐答案

getindex.(Ref(dict), keys)

您可以将它包装在 Ref 中，这样您就不需要 [] 了.

You can wrap it in Ref so you don't need to [] it.

这篇关于字典的矢量化索引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！