Ruby, like most languages, has the all-time favourite for loop. Interestingly, nobody uses it much - but let's leave the alternatives for the next exercise. Here's how you use a for loop in Ruby. Just run the code below to print all the values in the array.

Ok, your turn now. Copy the values less than 4 in the array stored in the source variable into the array in the destination variable.

Iteration is one of the most commonly cited examples of the usage of blocks in Ruby. The Array#each method accepts a block to which each element of the array is passed in turn. You will find that for loops are hardly ever used in Ruby, and Array#each and its siblings are the de-facto standard. We'll go into the relative merits of using each over for loops a little later once you've had some time to get familiar with it. Let's look at an example that prints all the values in an array.

Ok, now let's try the same thing we did with the for loop earlier - copy the values less than 4 in the array stored in the source variable to the array in the destination variable.