Floats and Integers

Quick reference

• 00:04 In this video, I want to talk about floats and integers, integers and floats.
• 00:08 In the last video we talked about math.
• 00:10 Math obviously deals with numbers.
• 00:12 Ruby handles numbers a couple of different ways, as an integer or a float.
• 00:16 So what's the difference between the two?
• 00:18 Well, an integer is just a round number.
• 00:20 41, 12, 0, those are just integers, right?
• 00:27 A float, on the other hand, is 19.99.
• 00:30 It has decimals, so any number with decimals is a float.
• 00:34 12.55, that's a float.
• 00:36 So there's a very real difference between the two, and
• 00:39 it's actually pretty important.
• 00:40 And a lot of times you need to know whether you're dealing with an integer
• 00:43 or a float.
• 00:44 So why is this important?
• 00:45 Well, let's go puts 10 divided by 3.
• 00:50 Now, if I pull up my calculator, and I take 10 divided by 3,
• 00:56 you see the answer is 3.3333333, right, to infinity.
• 01:02 Well, if we run it here, we save this and run our program, we see the answer is 3.
• 01:07 And we know that's just not true.
• 01:08 But what Ruby is doing here is Ruby is going okay, they want to use integers
• 01:13 because they didn't use decimal points, so I'm going to return an integer.
• 01:17 And it returns 3.
• 01:18 So there are certain times when you may want to do that.
• 01:21 There are very legitimate reasons to want to do that.
• 01:24 Other times, you're going to want to be more exact.
• 01:26 And in that case, you're going to use floats.
• 01:28 So to change this to a float, you just add decimals.
• 01:32 Go ahead and save this and run it.
• 01:35 And we get 3.33333, and it rounds up to 5.
• 01:38 So those are floats, those are integers, very important.
• 01:42 So one kind of weird thing that you have
• 01:45 to be aware of when it comes to floats is this.
• 01:49 Let's go ahead and let's go puts, and let's go 0.05 plus 1.
• 01:53 So you would expect the answer to be 1.05.
• 01:56 But you see right away we're getting this big angry red X, and
• 01:59 we know that's an error.
• 02:00 And the error message says floating literal anymore put 0 before dot, okay?
• 02:06 So if we run this, well, we already know, oops, I've gotta save this first.
• 02:10 If we save it and run it, we already know we're going to get an error.
• 02:13 But of course, we see the same exact thing.
• 02:15 And I talked a couple of videos ago about errors, and
• 02:18 this one even tells you what to do.
• 02:20 It says put 0 before dot.
• 02:21 And that's the problem.
• 02:22 Floats require 0 to begin with, 0.05 something, and
• 02:27 that has to do with the float method.
• 02:30 Then, it looks for a single integer followed by decimal.
• 02:34 But just remember, whenever you're dealing with below one decimals,
• 02:38 you always have to put a 0 in front.
• 02:39 Now, if we save this and run it, we get 1.05, just like that.
• 02:44 So that's interesting.
• 02:46 And you can play around with this a little bit.
• 02:47 You could see, if we save this and run it, if only one of the numbers
• 02:52 is an integer and one or them is a float, we still get a thing.
• 02:57 If we switch it around 10, 3.0, we save this and run it, again, same thing.
• 03:04 Doesn't matter how many decimals you go out, going to get the same answer.
• 03:08 So those are integers, those are floats.
• 03:10 In the next video, we're going to look at comparison operators.

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