如何从数组中获取一个随机元素而又不多次获取同一元素？ [英] How to grab a random element from an array without grabbing the same element more than once?

问题描述

当我使用 arc4random_uniform（）方法从数组中获取一个元素时，该数组中的同一元素通常会被多次获取。我正在尝试使数组中的每个元素仅被抓取一次。我尝试执行此操作的原因是 UITableView 中的多个单元格没有相同的文本。这是 UITableView 中单元格文本的数组：

  var definitions = [[用于携带法老，用于作为仪式携带尸体，具有平坦的甲板来承载农夫的宝物，每天，它都要绕着Ra进行世界各地的旅行， 
  

$ $$$$$

$由较小的船只拖曳，携带重物，用于官员/贵族的商务和休闲，随身携带大多数埃及人和一些物品 b
$ b

在我的 viewDidLoad（）方法中，我这样做是为了调用定义：

  self.boats = [Boats（name：definitions [Int（arc4random_uniform（7））]），小船（name：definitions [Int（arc4random_uniform（7））]），Boats（name：definitions [Int（arc4random_uniform（7））]），Boats（name：definitions [Int（arc4random_uniform（7））]），Boats（name ：definitions [Int（arc4random_uniform（7））]），船（名称：definitions [Int（arc4random_uniform（7））]），Boats（名称：definitions [Int（arc4random_uniform（7））]）] 
  

如何更改代码，使两个元素不会在 UITableView 中两次显示？谢谢！

解决方案

保留随机索引值的列表，如果该列表中包含后续随机索引，则跳过该列表并生成另一个随机索引。

When I grab an element from an array using the arc4random_uniform() method, the same element the array is often grabbed more than once. I am trying to make it so each element in the array is grabbed only once. The reason I'm trying to do this is so more than one cells in a UITableView don't have the same text. Here's the array for the text of the cells in the UITableView:

var definitions = ["Used to carry the pharoah","Used to carry bodies as a ceremony","Had a flat deck to carry a farmer's treasure","Daily, it made a trip around the world to carry Ra","Towed by smaller boats, carrying heavy objects","Used for business and pleasure by officials/nobles","Carried most Egyptians and some goods"]

In my viewDidLoad() method, I have done this to call random elements of definitions:

self.boats = [Boats(name: definitions[Int(arc4random_uniform(7))]),Boats(name: definitions[Int(arc4random_uniform(7))]),Boats(name: definitions[Int(arc4random_uniform(7))]),Boats(name: definitions[Int(arc4random_uniform(7))]),Boats(name: definitions[Int(arc4random_uniform(7))]),Boats(name: definitions[Int(arc4random_uniform(7))]),Boats(name: definitions[Int(arc4random_uniform(7))])]

How can I alter my code so two elements aren't displayed twice in my UITableView? Thank you!

解决方案

Keep a list of the random index values and if a subsequent random index is in that list, then skip it and generate another random index.

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