Search an array based on search text using Swift

Question

I am a newbie to swift and i have a new project. I am trying to do a search feature. I have a array of dictionaries, containing firstName and lastName as keys, i need to filter out people based on the firstName which contains the search string

let nameList : [Dictionary<String,String>] = 
[["firstName" : "John Sam","lastName" : "Smith"],
["firstName" : "Johnny","lastName" : "Smith"],
["firstName" : "Albert","lastName" : "Smith"],
["firstName" : "Alby","lastName" : "Wright"],
["firstName" : "Smith","lastName" : "Green"]]

As in objective C i could easily do with

[NSPredicate predicatewithformat:"firstName contains[c] %@",searchText] 

I also understand that the same predicate can be done on Swift .but i am looking for an equivalent Swift, so that i can gain how to use map and filter. Any help appreciated

Answer 1

A search corresponding to the predicate operator "CONTAINS[c]" can be achieved with rangeOfString() with the .CaseInsensitiveSearch option:

let searchText = "MITH"

let filtered = nameList.filter {
    return $0["firstName"]?.rangeOfString(searchText, options: .CaseInsensitiveSearch) != nil
}

// Result: [[firstName: Smith, lastName: Green]]

Swift 3:

let filtered = nameList.filter {
    return $0["firstName"]?.range(of: searchText, options: .caseInsensitive) != nil
}

Answer 2

You can filter by defining a function to filter by first, or just include the filter in a closure. Here's an excerpt that you can paste into a playground that demonstrates both options:

let nameList : [Dictionary<String,String>] =
[["firstName" : "John Sam","lastName" : "Smith"],
    ["firstName" : "Johnny","lastName" : "Smith"],
    ["firstName" : "Albert","lastName" : "Smith"],
    ["firstName" : "Alby","lastName" : "Wright"],
    ["firstName" : "Smith","lastName" : "Green"]]

func fn (x: Dictionary<String,String>) -> Bool {
    return x["firstName"] == "Johnny"
}

nameList.filter(fn)

var r = nameList.filter({$0["firstName"] == "Johnny"})

r

var s = nameList.filter({$0["lastName"] == "Smith"})

s

You can also filter the results of a filter to search for first and last name, e.g.

var result = (nameList.filter({$0["lastName"] == "Smith"})).filter({$0["firstName"] == "Johnny"})

See also: http://locomoviles.com/ios-tutorials/filtering-swift-array-dictionaries-object-property/