Swift 3简单搜索引擎

Question

我有一个字符串数组，其中包含用户输入的值。我有一个包含几个单词的字符串(字符串中的单词数是不同的)。每当字符串中的一个单词与数组中的一个单词匹配时，我都想增加一个Int。

我用的是这个方法：

var searchWordsArr: [String] = [] \\filled by user input

var message: String = "" \\random number of words

var numRelevantWords = 0

var i = 0

while i < self.searchWordsArr.count {
    i+=1
    if message.contains(self.searchWordsArr[i-1]) {
        numRelevantWords += 1
    }
}

在我的第一个示例中，字符串包含25个单词，数组包含3个单词。这三个字在字符串中总共出现了12次。用上述方法测得numRelevantWords值为2。

Answer 1

我会用regex。不久的将来，Swift将有本机正则表达式。但在此之前，你必须求助于基金会：

let words = ["the", "cat", "sat"]
let input = "The cat sat on the mat and the mat sat on the catastrophe"
var result = 0

let pattern = "\\b(" + words.joined(separator:"|") + ")\\b"
do {
    let regex = try NSRegularExpression(pattern: pattern, options: .caseInsensitive)
    let match = regex.matches(in: input, options: [], range: NSRange(location: 0, length: input.utf16.count))
    result += match.count // 7, that's your answer
} catch {
    print("illegal regex")
}

Answer 2

将它们添加到NSCountedSet中：

let searchWords = NSCountedSet()
searchWords.add("Bob")
searchWords.add("John")
searchWords.add("Bob")
print(searchWords.count(for: "Bob")) // 2

Answer 3

“纯”斯威夫特(无基金会)

let message = "aa bb aaaa ab ac aa aa"
let words = message.characters.split(separator: " ").map(String.init)
let search:Set = ["aa", "bb", "aa"]

let found = words.reduce(0) { (i, word) -> Int in
    var i = i
    i += search.contains(word) ? 1 : 0
    return i
}

print(found, "word(s) from the message are in the search set")

版画

4 word(s) from the the message are in the search set

更新(见讨论)

使用集

var search: Set<String> = []  // an empty set with Element == String
search.insert("aa")           // insert word to set 

使用阵列

var search: Array<String> = [] // an empty array
search.append("aa")            // append word to array

也许你是在找

let message = "the cat in the hat"
let words = message.characters.split(separator: " ").map(String.init)
let search:Set = ["aa", "bb", "pppp", "the"]

let found = search.reduce(0) { (i, word) -> Int in
    var i = i
    i += words.contains(word) ? 1 : 0
    return i
}

print(found, "word(s) from the search set found in the message")

版画

1 word(s) from the search set found in the message

如果你想提供与接受的答案相同的答案

let words = ["the", "cat", "sat"]
let input = "The cat sat on the mat and the mat sat on the catastrophe"

let inputWords = input.lowercased().characters.split(separator: " ").map(String.init)
let found = inputWords.reduce(0) { (i, word) -> Int in
    var i = i
    i += words.contains(word.lowercased()) ? 1 : 0
    return i
}

print(found, "word(s) from the search set found in the message")

版画

7 word(s) from the search set found in the message