Swift filter array of objects

contains() checks if a sequence contains a given element, e.g. if a String contains a given Character.

If your intention is to find all books where the name contains the substring "rt", then you can use rangeOfString():

var arr = englishBooks.filter {
    $0.nameOfBook.rangeOfString("rt") != nil
}

or for case-insensitive comparison:

var arr = englishBooks.filter {
    $0.nameOfBook.rangeOfString("rt", options: .CaseInsensitiveSearch) != nil
}

As of Swift 2, you can use

nameOfBook.containsString("rt") // or
nameOfBook.localizedCaseInsensitiveContainsString("rt")

and in Swift 3 this is

nameOfBook.contains("rt") // or
nameOfBook.localizedStandardContains("rt") // or
nameOfBook.range(of: "rt", options: .caseInsensitive) != nil

Sorry this is an old thread. Change you code slightly to properly init your variable 'nameOfBook'.

class book{
   var nameOfBook: String!
   init(name: String) {
      nameOfBook = name
   }
}

Then we can create an array of books.

var englishBooks = [book(name: "Big Nose"), book(name: "English Future 
Prime Minister"), book(name: "Phenomenon")]

The array's 'filter' function takes one argument and some logics, 'contains' function can take a simplest form of a string you are searching for.

let list1 = englishBooks.filter { (name) -> Bool in
   name.contains("English")
}

You can then print out list1 like so:

let list2 = arr1.map({ (book) -> String in
   return book.nameOfBook
})
print(list2)

// print ["English Future Prime Minister"]

Above two snippets can be written short hand like so:

let list3 = englishBooks.filter{ ($0.nameOfBook.contains("English")) }
print(list3.map({"\($0.nameOfBook!)"}))

SWIFT 4.0

In order to filter objects and get resultant array you can use this

self.resultArray = self.upcomingAuctions.filter {
                    $0.auctionStatus == "waiting"
                }

2020 | SWIFT 5.1:

public filterStr = ""

public var books: [Book] = []

public var booksFiltered: [Book] {
   get {
      filterStr.isEmpty
         ? books
         : books.filter { $0.alias.range(of: filterStr, options: .caseInsensitive) != nil }
   }
}

in case you want to delete an interval of object which has specific IDs (matchIDsToDelete) from an array of object (matches)

var matches = [Match]
var matchIDsToDelete = [String]
matches = matches.filter { !matchIDsToDelete.contains($0.matchID) }

I think this is more useful for lack of wrong typing situation.

englishBooks.filter( { $0.nameOfBook.range(of: searchText, options: .caseInsensitive) != nil}

In Swift 4.2 use the remove(where:) functionality. filter isn't doing well with memory, remove(where:) does the job better.

To do what you want:

englishBooks.removeAll { !$0.nameOfBook.contains("English") }