Gem Usage3:04 with Jason Seifer
Now that a gem is installed, we need to know how to use it.
Once a gem is installed, it is used by calling the
require statement followed by the name of the gem. If we were using the
money gem, it would look like this:
Now that we know what gem we want to use and 0:00 have it installed, we have to be able to use it in our program. 0:03 Let's see how that works now using work spaces. 0:07 So now that we have the money gem installed, let's go ahead and 0:11 see how to use it in one of our programs. 0:14 First, I'm actually going to scroll down the right side of the screen 0:17 on the ruby gem documentation page, and 0:20 I'm going to click the documentation link, and then we'll see what it gives us. 0:23 Right now, I'm going to click on the API documentation, and 0:32 then, let's see how to use it in one of our programs. 0:37 Well, we've done the gem install, so let's go ahead and see how to use it. 0:40 In this example, there's $10 US. 0:46 Now first, we'll need to require the gem, 0:49 s o let's go back to our work space and create a new file. 0:51 We're going to call this money example.rb. 0:58 Now once a gem is installed, the first thing that we need to do is require it. 1:05 So, we’ll require money. 1:10 If only it were that easy in life. 1:14 Now that it’s required we can use it, so I’m going to go back and 1:17 consult the documentation. 1:20 It looks like we can initialize a new money instance by calling the class name 1:23 money, and the word new, and then give it the number of cents in a currency. 1:27 Let's go ahead and try that. 1:33 And, for right now, let's just print that to the screen. 1:42 Now, I'm gonna click down into the console, and run this program, 1:49 and it gives us a money instance. 1:55 So, at this point, we've installed a gem, and used it in a very simple program. 2:00 Let's go ahead and create another one, more_money. 2:07 And let's print this to the screen as well. 2:22 Run this one more time, and 2:26 we can see that we have successfully added two units of money together. 2:29 And that's really all that's required to use a gem once we've got it installed. 2:35 Just use the require statement. 2:40 Ruby will then find the gem and import it for you in to your program. 2:43 Generally, the require statement is going to be the same name as the gem. 2:49 In this example it was called money. 2:54 If we had installed another gem, such as multi jason, 2:57 we would require multi jason instead. 3:00
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