Swift Loops: `for-in`

In this blog post, we will be discussing the for-in loop in Swift. The for-in loop is a versatile looping construct that can be used to iterate over a specific range of values or over the elements of a collection.

Looping with a Range Operator

The for-in loop can be used to iterate a specific number of times by utilizing the range operator. Here’s an example:

for index in 0...3 {
  // Code to be executed during each iteration
  print("Index is \(index)")
}

In this example, the loop will run four times, with the index variable taking on the values 0, 1, 2, and 3 during each iteration.

Looping over Collection Elements

The for-in loop is particularly handy when it comes to iterating over the elements of a collection, such as an array or a set. Here’s an example:

let list = ["a", "b", "c"]
for item in list {
  // Code to be executed for each item in the list
  print("Current item: \(item)")
}

In this case, the loop will iterate over each element in the list array, and the item variable will contain the value of the current element during each iteration.

Looping over Dictionary Elements

The for-in loop can also be used to iterate over the key-value pairs of a dictionary. Here’s an example:

let list = ["a": 1, "b": 2, "c": 3]
for (key, value) in list {
  // Code to be executed for each key-value pair in the dictionary
  print("Key: \(key), Value: \(value)")
}

In this example, the loop will traverse each key-value pair in the list dictionary, with the key variable holding the current key and the value variable holding the current value.

Conclusion

The for-in loop is a powerful construct in Swift that allows you to iterate over a range of values or the elements of a collection. By understanding how to use this loop effectively, you can streamline your code and perform repetitive tasks with ease.

Tags: Swift, for-in loop, loops, range operator, collection iteration, dictionary iteration