Swift SequenceType Extensions

SequenceExtensions.swift

extension SequenceType {

  // Index an array with a property. 
	@warn_unused_result
	func index<T: Hashable>(@noescape by indexFunc: (Generator.Element -> T)) -> [T: Generator.Element] {
		var dict: [T: Generator.Element] = [:]
		
		for element in self {
			let index = indexFunc(element)
            dict[index] = element
		}
		
		return dict
	}
}