Finding Large Arrays in Swift

Question

I have a JSON file for all airports in the world that I am trying to execute in a function, but it is very slow and I am trying to improve its performance. There are 9,500 entries in this JSON file (I would use the web API but could not find a free one, so I use this JSON file). My array is like:

var data = [Dictionary<String, AnyObject>]

Here's what one of the dictionaries looks like:

[DisplayText: YYZ, airportObject: {
    0 = 193;
    Altitude = 569;
    City = Toronto;
    Country = Canada;
    DST = A;
    IATA = YYZ;
    ICAO = CYYZ;
    Latitude = "43.677223";
    Longitude = "-79.630556";
    Name = "Lester B Pearson Intl";
    TZ = "America/Toronto";
    UTC = "-5";
}, DisplaySubText: Lester B Pearson Intl]

The goal is to have TextField autocomplete with the name of the airport that the user enters into the field. I wrote a function to filter these entries using user input. It works, however it is very slow and takes about 1 second for each letter entered, and the processor prints up to 50%.

Here is the function

func applyFilterWithSearchQuery(filter : String) -> [Dictionary<String, AnyObject>]
{
    //let predicate = NSPredicate(format: "DisplayText BEGINSWITH[cd] \(filter)")
    var lower = (filter as NSString).lowercaseString
    var filteredData = data.filter({
            if let match : AnyObject  = $0["DisplayText"]{
                //println("LCS = \(filter.lowercaseString)")
                return (match as NSString).lowercaseString.hasPrefix((filter as NSString).lowercaseString)
            }
            else{
                return false
            }
        })
    return filteredData
}

How to improve the performance of this feature?

Answer 1

.

• , applyFilterWithSearchQuery 1.
• ,
• NSPredicate, :

    func applyFilterWithSearchQuery(filter : String) -> [Dictionary<String, AnyObject>]
    {
        let predicate = NSPredicate(format: "DisplayText BEGINSWITH[cd] %@", filter)
        let filteredData = (self.data as NSArray).filteredArrayUsingPredicate(predicate!)
        return filteredData as [Dictionary<String, AnyObject>]
    }

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1%. ,