Swift Loops
At times, we may need to execute the same block of code multiple times. Ordinarily, statements are executed sequentially: the first statement in a function is executed first, followed by the second, and so on.
Programming languages provide various control structures that allow for more complicated execution paths.
Loop statements enable us to execute a statement or group of statements multiple times. Below is a flowchart of loop statements in most programming languages:
Loop Types
Swift provides the following types of loops. Click on the links to see detailed descriptions of each type:
| Loop Type | Description |
|---|---|
| for-in | Iterates over all elements in a collection, such as a range of numbers, elements in an array, or characters in a string. |
| for loop | This type of loop has been deprecated in Swift 3. It was used to repeatedly execute a series of statements until a specific condition was met, typically by incrementing a counter after each loop iteration. |
| while loop | Executes a set of statements repeatedly as long as the condition is true, until the condition becomes false. |
| repeat...while loop | Similar to the while statement, but it executes the loop block once before checking the condition. |
Loop Control Statements
Loop control statements alter the execution sequence of your code, allowing you to jump to different parts of the code. Swift provides the following loop control statements:
| Control Statement | Description |
|---|---|
| continue statement | Instructs a loop to stop the current iteration and immediately start the next iteration. |
| break statement | Terminates the current loop. |
| fallthrough statement | If a case is executed and you want to continue executing the next case, you need to use the fallthrough keyword. |