CODEWITHSUNDEEP
iosarraysswiftenumerate
user5849987
user5849987

Reputation:

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

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!

Upvotes: 0

Views: 146

Answers (1)

Brad Larson
Brad Larson

Reputation: 170317

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.

Upvotes: 4

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