In this lesson we will learn about different ways to repeat actions in our programs with loops.

Introduction to Looping

Congratulations! We are almost done with this lesson, but before we finish, let’s review loops.

Loops instruct the computer to repeat an activity without duplicating any code. Coders use loops to repeat actions. We discussed three types of loops:

* While loops
* For loops
* For-each loops

### While Loops

When we don’t know how many times the loop needs to be repeated, we use a while loop. A while loop repeats as long as a certain condition is met.

### For Loops

For-loops are used when we know how many times we want the code to repeat. We supply the code with a value, and the computer completes the task that amount of times.

### For Each Loops

For each loops perform actions on each item in a list.

To repeat actions, use loops in your next project!


Review

Imagine we have a list of addresses to which we want to deliver mail. We would want the driver to go to each address in the list and drop off the package. 

To go through that list of addresses, we would use a for-each loop. A for-each loop is a simple way to write code that works on each item in a list! We might program the delivery with code that looks like:

```
addresses = {"1 First St", "45 Eighth St", "90 Seventh St"};
    for (each address in addresses) {
     Drive to the address
     Deliver package for that address
}  
```  


This code will have the driver deliver the packages in the order of the list.

Use for-each loops in your programs to work on each item in a list!



For Each Loops


*For loops* are used when we know how many times we want a particular set of instructions to run. For loops allow us to communicate:

- When to start our loop
- How many times to repeat
- What to do after repeating

A for loop which starts at 2 and counts up to 5 might look like:

```
for (start at 2; stop at 5; go up by 1){
  print current number
}
// Would output: 2 3 4 5
```
 
For loops let us repeat actions a certain number of times. Now that we know how to use for loops, let’s practice!

For Loops

When writing programs, we often have logic when need to repeat.  We could write out the logic multiple times, but repeating code can take a lot of time and be difficult to change.

In this lesson, we will discuss loops. Loops are a way we can define actions we want to repeat, as well as the way they are repeated.

We will discuss three types of loops in this lesson, which manage repetition in three different ways:

* While Loops
* For Loops
* For Each Loops

We will explore each in detail over the following exercises.


Introduction to Loops

A *while loop* allows us to repeat an action until a certain condition is met. 

While loops are similar to if statements. An if statement executes code *if* a condition is true. A while loop will keep repeating its code *while* a condition is true.

The code for a while loop might look like this:

```
While (I am not home) {
  Take step toward home
}
```

While loops allow us to move towards a goal until it is reached. Let's practice!