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)
}
}
}
Update for Swift 5:
extension Array where Element: Equatable {
/// Remove first collection element that is equal to the given `object` or `element`:
mutating func remove(element: Element) {
if let index = firstIndex(of: element) {
remove(at: index)
}
}
}