More Array Methods

We’ve learned each, but there are many other array methods, almost as many as there are string methods. In fact, some of them (such as length, reverse, +, and *) work just like they do for strings, except they operate on the slots of the array rather than on the letters of the string. Others, such as last and join, are specific to arrays. Still others, such as push and pop, actually change the array. And just as with the string methods, you don’t have to remember all of these, as long as you can remember where to find out about them (and that would be right here).

Let’s look at to_s and join. to_s gives you a nice readable string description, in this case making it clear that this is an array of strings. join calls to_s on the individual elements of the array (which does nothing in this case, since they are already strings), and it adds the string you provide in between those.

Two hundred times?! No more sugar for me!

Whew! It’s good puts treats arrays differently from other objects; that would have been a boring couple of pages if puts had written something 200 times. With arrays, puts calls puts on each of the objects in the array. That’s why calling puts on an empty array 200 times doesn’t do anything; the array doesn’t contain anything, so there’s nothing to puts. Doing nothing 200 times is still doing nothing (unless you’re playing a role-playing game, in which case you just leveled!). Try putsing an array containing other arrays; did it do what you expected?

Now let’s take a look at push, pop, and last. The methods push and pop are sort of opposites, like + and - are. push adds an object to the end of your array, and pop removes the last object from the array (and tells you what it was). last is similar to pop in that it tells you what’s at the end of the array, except that it leaves the array alone. Again, push and pop actually change the array: