Use contains instead:

let arr = ["Hello","Bye","Halo"]
let filtered = arr.filter { $0.contains("lo") }
print(filtered)

Output

["Hello", "Halo"]

Thanks to @user3441734 for pointing out that functionality is of course only available when you import Foundation

you can try using searchBar for solving this kind of problems. Here is an example of how you use the searchBar;

import UIKit

class ViewController: UIViewController,UISearchBarDelegate {

    //MARK: - IBOutlets
    @IBOutlet weak var serachBar: UISearchBar!
    
    //MARK: - Variables
    var rawData:[String] = ["Taha","Yasin","Samet","Sumeyye","Seda","Esra","Muhammet","Zeynep","Ishak","Fatma"]
    var filteredData:[String]!

    override func viewDidLoad() {

        super.viewDidLoad()
        
        serachBar.delegate = self
        filteredData = rawData
    }

    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        filteredData = searchText.isEmpty ? rawData : rawData.filter {
            $0.contains(searchText)
        }
        //It prints the data from the filtered array contains the text that you searched from the search bar and the print method will be called after every caracter that you add the search bar.
        print(filteredData)
    }
}

[Updated for Swift 2.0]

As NSString is toll-free bridged to Swift String, just avoid the coercions with:

  3> ["abc", "bcd", "xyz"].filter() { nil != $0.rangeOfString("bc") }
$R1: [String] = 2 values {
  [0] = "abc"
  [1] = "bcd"
}

But, if you think allValues aren't strings:

(keywords.allValues as? [String]).filter() { nil != $0.rangeOfString("bc") }

which returns an optional array.

Try like this.

let itemsArray = ["Google", "Goodbye", "Go", "Hello"]
let searchToSearch = "go"

let filteredStrings = itemsArray.filter({(item: String) -> Bool in

     var stringMatch = item.lowercaseString.rangeOfString(searchToSearch.lowercaseString)
     return stringMatch != nil ? true : false
})

filteredStrings will contain the list of strings having matched sub strings.

In Swift Array struct provides filter method, which will filter a provided array based on filtering text criteria.

The simplest way

func filterArray(filter : String)
{
    let filtered = mainArray.filter { $0.contains(filter) }
print(filtered)

}

You are getting this error because unfortunately range is not available in Linux. If you had access to a machine with macOS this would work.

As @Hamish said, I was completely wrong, you have to import Foundation in order to use range or contains on String (even though you can call contains on string.characters without importing Foundation).

Add this line to the beginning of your code:

import Foundation

I would write this something like this I think...

// make it a function that takes everything it needs and returns a result array
func filteredCountryArray(countryArray: [[String]], searchString: String) -> [[String]] {
    guard !searchString.isEmpty else {
        // search string is blank so return entire array...
        return countryArray
    }

    // Filter the data array and get only those countries that match the search text.
    return countryArray.filter { match in
        // check array is long enough to get [1] out of it
        guard match.count >= 2 else {
            return false
        }

        let matchText = match[1]
        return matchText.range(of: searchString, options: .caseInsensitive) != nil
    }
}

plazaDictionary is a very odd name to give to an array. It is an array, not a dictionary.

What you should probably do here is create some data objects (structs, classes, enums, etc...) that hold the data in a better format than a nested array.

This should do what you want for now though.

EDIT

Having another think about it, I would also change the serachString and the array into input parameters...