Loops

Loops can be used to repeat pieces of code an arbitrary number of times. All loops can be broken out of using the break keyword, and you can jump to the next iteration by using the continue keyword.

For loops

A for loop comes in two forms, and is used when the number of times a loop must occur is known.

For-in loop

A for-in loop is used to loop over a certain collection of data, and use the for keyword, a variable name, the in keyword and then the data to loop over (either an array or an object that extends Iterable).

// Loop over each item in the list
for item in list {
  //body
}

// Loop in the range of 0 to 10
for num in 0 .. 10 {

}

Traditional for loop

A traditional for loop is used to loop a certain number of times, rather than over a collection of data. It uses the for keyword, a statement to execute before the loop starts, a looping condition and a statement to execute at the end of each iteration.

// Loop 10 times
for var x = 0, x < 10, x++ {
  // body
}

While loop

A while loop is used when the number of times to loop is unknown, and the loop should instead terminate when a certain condition is met. It uses the while keyword followed by the looping condition.

// Loop 10 times
var x = 0
while x < 10 {
  // body
}

Break and continue

To break out of the last entered loop, use the break keyword, this will resume all code after the end of the loop. To continue with the next iteration of the loop, use the continue keyword.