Swift Tutorial - Swift for statement

The for loop executes a set number of times.

We use the for keyword along with an ending condition and a for-loop statement.

Example

The following loop statement prints out 1 through 10 to the console.

for var i = 1; i <= 10; ++i {
   println("i = \(i)")
}

The code above generates the following result.

Nested for statement

for x in 1...3 {
    for y in 1...3 {
        println("x = \(x), y = \(y)")
    }
}

The code above generates the following result.

Nested for loop with continue

If you wanted to skip any value where y equals 2, you could just include a continue statement right inside the innermost loop.

for x in 1...3 {
    for y in 1...3 {
        if y == 2{
            continue
        }
        println("x = \(x), y = \(y)")
    }
}

The code above generates the following result.

for-in Loop

Use the for in loop to iterate over items in collections such as arrays and dictionaries.

To use a for in loop, specify a local variable name and the collection you are iterating over.

let names = ["A", "B", "C"]

for n in names{
    println(n)
}

let inventory = [1:"SQL", 2:"Java", 3:"C"]

for (key,item) in inventory{
    println("\(key) : \(item)")
}

The following code iterates with Range Operators.

var result = 0

for i in 1...3{
   ++result
}

The above code 3 uses a range operator to specify a range between 1 and 3 and uses this to increment the variable result.