arrays - Swift 2 从包含字符串的数组中删除对象

Question

我在 Swift 2 中有字符串数组：

var myList              : [String] = []

我里面有动态字符串，我用*字符 myList 例子来爆炸它们：

   print(myList[0])  output = 2018-04-05*type2*namea
   print(myList[1])  output = 2018-04-05*type2*nameb
   print(myList[2])  output = 2018-04-05*type3*nameb
   print(myList[3])  output = 2018-04-06*type3*named

我想删除myList 中有type3的对象：

如果在相同的日期和相同的名字并且有type2的

必须是这样的我的字符串：

   print(myList[0])  output = 2018-04-05*type2*namea
   print(myList[1])  output = 2018-04-05*type2*nameb
   print(myList[2])  output = 2018-04-06*type3*named

必须删除以下项目：

   print(myList[2])  output = 2018-04-05*type3*nameb

如果之前的 type2 基本上具有相同的日期和相同的名称，我想删除 myList 中的 type3 。

解释：

2018-04-05*type2*nameb并且2018-04-05*type3*nameb，具有相同的日期和相同的名称，但2018-04-05*type3*nameb之前有type2 (2018-04-05*type2*nameb) ？所以必须删除2018-04-05*type3*nameb 行

我该怎么做？

标签： arraysswiftstringswift2

Answer 1

这个操场代码将做你想做的事：

//: Playground - noun: a place where people can play

import UIKit

let myList = ["2018-04-05*type2*namea",
              "2018-04-05*type2*nameb",
              "2018-04-05*type3*nameb",
              "2018-04-06*type3*named"]

//Define a class that lets us map from a string to a date, type, and name string
class ListEntry {
    let fullString: String

    //define lazy vars for all the substrings
    lazy var subStrings: [Substring] = fullString.split(separator: "*")
    lazy var dateString = subStrings[0]
    lazy var typeString = subStrings[1]
    lazy var nameString = subStrings[2]

    //Create a failable initializer that takes a full string as input 
    //and tries to break it into exactly 3 substrings
    //using the "*" sparator
    init?(fullString: String) {
        self.fullString = fullString
        if subStrings.count != 3 { return nil }
    }
}

print("---Input:---")
myList.forEach { print($0) }
print("------------")

//Map our array of strings to an array of ListEntry objects
let items = myList.compactMap { ListEntry(fullString: $0) }

//Create an output array
var  output: [String] = []

//Loop through each item in the array of ListEntry objects, getting an index for each
for (index,item) in items.enumerated() {

    //If this is the first item, or it dosn't have  type == "type3", add it to the output
    guard index > 0,
        item.typeString == "type3" else {
            print("Adding item", item.fullString)
            output.append(item.fullString)
            continue
    }
    let previous = items[index-1]

    /*
     Add this item if
        -the previous type isn't "type2"
        -the previous item's date doesn't match this one
        -the previous item's name doesn't match this one
     */
    guard previous.typeString == "type2",
        item.dateString == previous.dateString,
        item.nameString == previous.nameString else {
            print("Adding item", item.fullString)
            output.append(item.fullString)
            continue
    }
    print("Skipping item ", item.fullString)
}
print("\n---Output:---")
output.forEach { print($0) }

上面代码的输出是：

---Input:---
2018-04-05*type2*namea
2018-04-05*type2*nameb
2018-04-05*type3*nameb
2018-04-06*type3*named
------------
Adding item 2018-04-05*type2*namea
Adding item 2018-04-05*type2*nameb
Skipping item  2018-04-05*type3*nameb
Adding item 2018-04-06*type3*named

---Output:---
2018-04-05*type2*namea
2018-04-05*type2*nameb
2018-04-06*type3*named