Find an object in array?

Question

SWIFT 5

Check if the element exists

if array.contains(where: {$0.name == "foo"}) {
   // it exists, do something
} else {
   //item could not be found
}

Get the element

if let foo = array.first(where: {$0.name == "foo"}) {
   // do something with foo
} else {
   // item could not be found
}

Get the element and its offset

if let foo = array.enumerated().first(where: {$0.element.name == "foo"}) {
   // do something with foo.offset and foo.element
} else {
   // item could not be found
}

Get the offset

if let fooOffset = array.firstIndex(where: {$0.name == "foo"}) {
    // do something with fooOffset
} else {
    // item could not be found
}

You can use the index method available on Array with a predicate (see Apple's documentation here).

func index(where predicate: (Element) throws -> Bool) rethrows -> Int?

For your specific example this would be:

Swift 5.0

if let i = array.firstIndex(where: { $0.name == "Foo" }) {
    return array[i]
}

Swift 3.0

if let i = array.index(where: { $0.name == Foo }) {
    return array[i]
}

Swift 2.0

if let i = array.indexOf({ $0.name == Foo }) {
    return array[i]
}

FWIW, if you don't want to use custom function or extension, you can:

let array = [ .... ]
if let found = find(array.map({ $0.name }), "Foo") {
    let obj = array[found]
}

This generates name array first, then find from it.

If you have huge array, you might want to do:

if let found = find(lazy(array).map({ $0.name }), "Foo") {
    let obj = array[found]
}

or maybe:

if let found = find(lazy(array).map({ $0.name == "Foo" }), true) {
    let obj = array[found]
}

Swift 3

If you need the object use:

array.first{$0.name == "Foo"}

(If you have more than one object named "Foo" then first will return the first object from an unspecified ordering)

You can filter the array and then just pick the first element, as shown in Find Object with Property in Array.

Or you define a custom extension

extension Array {

    // Returns the first element satisfying the predicate, or `nil`
    // if there is no matching element.
    func findFirstMatching<L : BooleanType>(predicate: T -> L) -> T? {
        for item in self {
            if predicate(item) {
                return item // found
            }
        }
        return nil // not found
    }
}

Usage example:

struct T {
    var name : String
}

let array = [T(name: "bar"), T(name: "baz"), T(name: "foo")]

if let item = array.findFirstMatching( { $0.name == "foo" } ) {
    // item is the first matching array element
} else {
    // not found
}

---

In Swift 3 you can use the existing first(where:) method (as mentioned in a comment):

if let item = array.first(where: { $0.name == "foo" }) {
    // item is the first matching array element
} else {
    // not found
}