Split an NSString to access one particular piece

NSArray* foo = [@"10/04/2011" componentsSeparatedByString: @"https://stackoverflow.com/"];
NSString* firstBit = [foo objectAtIndex: 0];

Update 7/3/2018:

Now that the question has acquired a Swift tag, I should add the Swift way of doing this. It’s pretty much as simple:

let substrings = "10/04/2011".split(separator: "https://stackoverflow.com/")
let firstBit = substrings[0]

Although note that it gives you an array of Substring. If you need to convert these back to ordinary strings, use map

let strings = "10/04/2011".split(separator: "https://stackoverflow.com/").map{ String($0) }
let firstBit = strings[0]

let firstBit = String(substrings[0])