如何接收 [TweetSentimentClassifierInput] 物件陣列的輸出以將其進一步發送到我的預測模型？
我有陣列但在一個閉包內，這使它無法作為方法輸出回傳。如果我在閉包外初始化一個空陣列，那么輸出總是一個空陣列，因為 fetch 閉包需要時間才能完成。
代碼
struct TweetFetcher {
let tweetCount = 100
let swifter = Swifter(consumerKey: key, consumerSecret: secret)
func fetchTweets(with searchText: String) -> [TweetSentimentClassifierInput] {
swifter.searchTweet(using: searchText, lang: "en", count: tweetCount, tweetMode: .extended) {(results, searchMetadata) in
var tweets = [TweetSentimentClassifierInput]()
let data = results.description.data(using: .utf8)
do {
let decodedData = try JSONDecoder().decode([TweetData].self, from: data!)
} catch {
print("Error with decoding, \(error)")
}
for tweet in decodedData {
let tweetForClassification = TweetSentimentClassifierInput(text: tweet.full_text)
tweets.append(tweetForClassification)
}
} failure: { (error) in
print("Error with the Twitter API request, \(error)")
}
}
}
如何從閉包中回傳一個非空陣列作為方法輸出？
uj5u.com熱心網友回復：
您應該使用一個completionHandler概念來實作這樣的異步操作：
struct TweetFetcher {
let tweetCount = 100
let swifter = Swifter(consumerKey: key, consumerSecret: secret)
func fetchTweets(with searchText: String, completion: @escaping ([TweetSentimentClassifierInput]?, Error?) -> Void) {
swifter.searchTweet(using: searchText, lang: "en", count: tweetCount, tweetMode: .extended) {(results, searchMetadata) in
var tweets = [TweetSentimentClassifierInput]()
let data = results.description.data(using: .utf8)
do {
let decodedData = try JSONDecoder().decode([TweetData].self, from: data!)
} catch {
print("Error with decoding, \(error)")
completion(nil, error)
}
for tweet in decodedData {
let tweetForClassification = TweetSentimentClassifierInput(text: tweet.full_text)
tweets.append(tweetForClassification)
}
completion(tweets, nil)
} failure: { (error) in
print("Error with the Twitter API request, \(error)")
completion(nil, error)
}
}
}
用法
let fetcher = TweetFetcher()
fetcher.fetchTweets(with: "Keyword...") { tweets, error in
if let error = error {
print(error.localizedDescription)
} else {
// Use tweets array content here ...
}
}
uj5u.com熱心網友回復：
以異步方式轉換此方法，將閉包[TweetSentimentClassifierInput]作為閉包引數傳遞，并將錯誤作為輔助閉包引數傳遞，
func fetchTweets(with searchText: String, finished: ((_ sentiments: [TweetSentimentClassifierInput]?,_ error: Error?) -> Void)) {
swifter.searchTweet(using: searchText, lang: "en", count: tweetCount, tweetMode: .extended) {(results, searchMetadata) in
var tweets = [TweetSentimentClassifierInput]()
let data = results.description.data(using: .utf8)
do {
let decodedData = try JSONDecoder().decode([TweetData].self, from: data!)
} catch {
print("Error with decoding, \(error)")
}
for tweet in decodedData {
let tweetForClassification = TweetSentimentClassifierInput(text: tweet.full_text)
tweets.append(tweetForClassification)
}
finished(tweets, nil)
} failure: { (error) in
print("Error with the Twitter API request, \(error)")
finished(nil, error)
}
}
轉載請註明出處，本文鏈接：https://www.uj5u.com/qukuanlian/373024.html