在Swift中创建包含不同类型的多维数组 [英] Creating multi-dimensional arrays containing different types in Swift

问题描述

我想在Swift中创建一个多维数组，然后从

I want to create a multi-dimensional array in Swift and following on from this post on creating multi-dimensional arrays, I came up with:

var itemList: [[(String, Date, Double, Int)]] = []

let itemID = purchases["itemID"] as! String
let purchase_date = purchases["purchase_date"] as! Date
let purchase_date_ms = purchases["purchase_date_ms"] as! Double
let quantity = purchases["quantity"] as! Int

itemList.append([(itemID, purchase_date, purchase_date_ms, quantity)])

这一切似乎都还可以，但是当我尝试使用以下方法获取数据时:

This all seems ok but when I try to get the data back out with:

var subPurchaseDate: Date
subPurchaseDate = itemList[0][1]

尝试从数组中读取"purchase_date"值，但出现错误无法将类型'(String，Date，Double，Int)'的值分配为'Date'"，并且

to try to read the "purchase_date" value from the array I get the error "Cannot assign value of type '(String, Date, Double, Int)' to type 'Date'", and

switch itemList[iloop][0] {
        ...
        }

给出类型为'String'的表达模式不能与类型为'(String，Date，Double，Int)'的值匹配"'

gives "Expression pattern of type 'String' cannot match values of type '(String, Date, Double, Int)'"

关于它为什么不采用我要在<array>[i][j]中指定的元素的值/类型的任何线索，但似乎却试图采用<array>[i]?我没看到什么?

Any clues as to why it's not taking the value/type of the element that I'm trying to specify in <array>[i][j] but seems to be trying to take <array>[i]? What am I not seeing?

推荐答案

您已将元组值存储在数组中.因此，通过提供索引位置来访问元组的内容.

You have stored tuple value inside array. so, access the contents of a tuple by providing the index position .

subPurchaseDate = itemList[0][1].0 // for string value
subPurchaseDate = itemList[0][1].1 // for date
subPurchaseDate = itemList[0][1].2 // for Double
subPurchaseDate = itemList[0][1].3 // for Int

您也可以使用其命名值进行访问.

You can also access using it's named value.

 var itemList: [[(stringValue: String, dateVal: Date, doubleValue: Double, intValue: Int)]] = []

// append elements in `itemList`
itemList.append([(stringValue: itemID, dateVal: purchase_date, doubleValue: purchase_date_ms, intValue: quantity)])

// access using it's named value

subPurchaseDate = itemList[0][1].stringValue // for string value
subPurchaseDate = itemList[0][1].dateVal // for date
subPurchaseDate = itemList[0][1].doubleValue // for Double
subPurchaseDate = itemList[0][1].intValue // for Int

这篇关于在Swift中创建包含不同类型的多维数组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！