How are arrays structured in the Swift language?

Arrays in Swift are ordered collections of elements of the same type. They are value types (structures) as opposed to NSArray in Objective-C.

Key features:

• Type safety: Arrays contain elements strictly of one type. Attempting to add an element of a different type results in a compile-time error.
• Order: Elements are stored in a specific sequence and are accessible by index, starting from 0.
• Mutability: Arrays can be mutable (if declared with var) or immutable (if declared with let).
• Value Type: When assigning an array to a new variable or passing it to a function, copying occurs (copy-on-write). This means modifications to the copy do not affect the original until the first actual modification, optimizing performance.

Main operations:

• Creation:

  // Empty array
  var emptyArray: [Int] = []
  // Array with initial values
  var numbers = [1, 2, 3]
  

• Accessing elements:

  let firstElement = numbers[0]
  

• Adding elements:

  numbers.append(4)
  numbers += [5, 6]
  

• Removing elements:

  numbers.remove(at: 0)
  numbers.removeLast()
  

• Iteration:

  for number in numbers {
      print(number)
  }
  

• Getting the count of elements:

  let count = numbers.count
  

Arrays support various useful methods such as filter, map, reduce for functional transformations.