Erica Sadun

Where technology meets something or other

Swift: ObjC-like Array index

One for the road. A simple array extension that returns the index of an object and removes an item

extension Array {
    func indexOfObject(object : AnyObject) -> NSInteger
    {
        return (self as NSArray).indexOfObject(object)
    }
    
    mutating func removeObject(object : AnyObject)
    {
        let index = self.indexOfObject(object)
        if (index != NSNotFound) {
            self.removeAtIndex(index)
        }
    }
}
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5 Comments

  • Erica, check this out: http://cl.ly/image/1V1A3G360V1h

    In short, arrays in swift are mutable, but copied on length changes.

  • Thanks for testing that out!

  • It’s worth noting that the removeObject method on ObjC NSArray removes ALL occurrence of that object from the NSArray, while this only removes the first occurrence. I threw up something quick that should replicate the actual functionality of removeObject here: https://gist.github.com/ankushg/5c3fb3fb21cb1463875b

  • The real answer, of course, is to make your class adopt Equatable. Now you have a completely Swift-based solution: you can call find and removeAtIndex on an Array of that class.

  • What will `(self as NSArray)` do with an array containing value types?