如何访问向量clojure的向量中的特定元素 [英] How do I access a specific element in a vector of vectors clojure

问题描述

如果我有一个向量定义为

 （def matrix [[1 2 3] [4 5 6]]] 
  

如何在clojure中访问向量的向量中的随机元素？我不断地看到人们在网上说，使用向量在列表上的好处之一是你获得随机访问，而不是通过列表递归，但我还没有能够找到允许我这样做的功能。我习惯于在c + +其中我可以做矩阵[1] [1]，它会返回第二个向量的第二个元素。

我不得不通过我的向量一次循环一个元素，还是有更简单的方法来访问特定的元素？

  user = > （def matrix [[1 2 3] [4 5 6]]）
 user => （矩阵1）
 [4 5 6] 
 user => （（matrix 1）1）
 5 
  

由于 docs说：

向量实现IFn，用于调用一个参数的invoke（），他们假定它是一个索引并且自己就像是通过nth查找，即向量是它们的索引的函数。

If I have a vector defined as

(def matrix [[1 2 3][4 5 6]])

How in clojure do I access a random element in a vector of vectors? I keep seeing people say online that one of the benefits to using a vector over a list is that you get random access instead of having to recurse through a list but I haven't been able to find the function that allows me to do this. I'm used to in c++ where I could do matrix[1][1] and it would return the second element of the second vector.

Am I stuck having to loop one element at a time through my vector or is there an easier way to access specific elements?

解决方案

Almost like you would do it in C++:

user=> (def matrix [[1 2 3][4 5 6]])
user=> (matrix 1)
[4 5 6]
user=> ((matrix 1) 1)
5

As the docs say:

Vectors implement IFn, for invoke() of one argument, which they presume is an index and look up in themselves as if by nth, i.e. vectors are functions of their indices.

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