unable to find enumerate() func in Swift standard library reference

Question

I'm new to Swift and is learning the concept of Array. I saw the code below from "swift programming language 2.1".

var array = [1,2,3,4,5]
for (index, value) in array.enumerate() {
    print("\(value) at index \(index)")
}

I want to read a bit more about the enumerate() func so I looked up the Apple developer's page on Array, however, I could not find a func named enumerate() on this page. Am I looking at the wrong place or is there something I am missing? Coudl someone please give me a hand? Thanks in advance for any help!

Answer 1

When you encounter a Swift standard library function or method that you can't find documentation on, command-click on it in Xcode. That will take you to its definition, which in this case is

extension SequenceType {
    /// Return a lazy `SequenceType` containing pairs (*n*, *x*), where
    /// *n*s are consecutive `Int`s starting at zero, and *x*s are
    /// the elements of `base`:
    ///
    ///     > for (n, c) in "Swift".characters.enumerate() {
    ///         print("\(n): '\(c)'")
    ///       }
    ///     0: 'S'
    ///     1: 'w'
    ///     2: 'i'
    ///     3: 'f'
    ///     4: 't'
    @warn_unused_result
    public func enumerate() -> EnumerateSequence<Self>
}

What the above states is that enumerate() gives you back a tuple for each value in your collection, with the first element in the tuple being the index of the current item and the second being the value of that item.