Array extension to remove object by value

Question

extension Array {
    func removeObject(object: T) {
        var index = find(self, object)
        self.removeAtIndex(index)
    }
}


        

Answer 1

As of Swift 2, this can be achieved with a protocol extension method. removeObject() is defined as a method on all types conforming to RangeReplaceableCollectionType (in particular on Array) if the elements of the collection are Equatable:

extension RangeReplaceableCollectionType where Generator.Element : Equatable {

    // Remove first collection element that is equal to the given `object`:
    mutating func removeObject(object : Generator.Element) {
        if let index = self.indexOf(object) {
            self.removeAtIndex(index)
        }
    }
}

Example:

var ar = [1, 2, 3, 2]
ar.removeObject(2)
print(ar) // [1, 3, 2]

Update for Swift 2 / Xcode 7 beta 2: As Airspeed Velocity noticed in the comments, it is now actually possible to write a method on a generic type that is more restrictive on the template, so the method could now actually be defined as an extension of Array:

extension Array where Element : Equatable {

    // ... same method as above ...
}

The protocol extension still has the advantage of being applicable to a larger set of types.

Update for Swift 3:

extension Array where Element: Equatable {

    // Remove first collection element that is equal to the given `object`:
    mutating func remove(object: Element) {
        if let index = index(of: object) {
            remove(at: index)
        }
    }
}

Answer 2

I was able to get it working with:

extension Array {
    mutating func removeObject<T: Equatable>(object: T) {
        var index: Int?
        for (idx, objectToCompare) in enumerate(self) {
            let to = objectToCompare as T
            if object == to {
                index = idx
            }
        }

        if(index) {
            self.removeAtIndex(index!)
        }
    }
}

Answer 3

With using protocol extensions in swift 2.0

extension _ArrayType where Generator.Element : Equatable{
    mutating func removeObject(object : Self.Generator.Element) {
        while let index = self.indexOf(object){
            self.removeAtIndex(index)
        }
    }
}