Swift 4编程用于过滤具有特定条件的大型数组

Question

请注意，我的问题仅针对 Swift 4 语法。我有笨重/大 字符串数组，我想过滤它以获取其中以某些特定字符/子字符串。这意味着我需要我的数组中的每个String匹配以一些子字符串开头。我找到了不同的链接，它为我提供了 Objective-C 的代码，我无法在 Swift 4 中实现它，因为 Swift 4 < / strong>即可。我通过在for循环中迭代我的数组手动解决了我的问题，但它给出了非常慢的结果所以我不想在这里使用任何循环，所以任何帮助都会有用。提前致谢。请参阅下面的代码：

func search() -> Void {
        var dummyStringsArray:[String] = ["Hotel Restaurants","Restaurants","Certified Green Restaurant(R)","Japnies Food Restauarants","Grill Restaurants","Restaurant Equipment","Wholsale Restaurant Fixtures","American Food","Wholsale Restaurant Supplies","Veg Restaurants","Barbecue Restaurants","Non-Veg Restaurants"]
        var displayDataArray:[String] = []
        let searchString:NSString = (textField.text!).lowercased() as NSString
        for string in self.dummyStringsArray {
            let mainString:NSString = string.lowercased() as NSString
            if mainString.length >= searchString.length {
                let compareString = String(mainString.substring(to: searchString.length))
                if searchString as String == compareString {
                    displayDataArray.append(string)
                }
            }
        }
    }

因此，如果我在textField中输入文字为＆＃39; 重新＆＃39;那么它应该返回包含＆＃34;餐厅＆＃34;，＆＃34;餐厅设备＆＃34;等值的displayDataArray。

Answer 1

我认为你不能在没有任何循环的情况下这样做，因为你需要经历所有的元素

但我可以使用$days=$model->days; // comma saperated days $days=explode(',',$days); // converting days into array $count=0; $start_date = $model->activity_start_date; // i.e. 2018-03-27 $end_date = date('Y-m-d'); while(strtotime($start_date) <= strtotime($end_date)){ if(in_array(date("N",strtotime($start_date)),$days)){ // check for day no $count++; } $start_date = date ("Y-m-d", strtotime("+1 day", strtotime($start_date))); } 函数为您提供更优雅的解决方案：

filter

Answer 2

在传递range(of:options:)和.caseInsensitive的选项时，使用.anchored可能会获得最佳效果。

func search() -> Void {
    let dummyStringsArray = ["Hotel Restaurants","Restaurants","Certified Green Restaurant(R)","Japnies Food Restauarants","Grill Restaurants","Restaurant Equipment","Wholsale Restaurant Fixtures","American Food","Wholsale Restaurant Supplies","Veg Restaurants","Barbecue Restaurants","Non-Veg Restaurants"]
    let searchString = textField.text!
    let displayDataArray = dummyStringsArray.filter { $0.range(of: searchString, options: [ .caseInsensitive, .anchored ]) != nil }
}