Multiple Conditional Comparison Operators

Quick reference

• 00:04 In the last video we talked about conditional statements just so
• 00:08 important programming and very easy to use.
• 00:10 In this video,
• 00:11 I want to talk about multiple comparison operators in your conditional statement.
• 00:15 So, remember the format let's get rid of all this stuff here.
• 00:21 And so, we have if, and our comparison operator,
• 00:24 our conditional statement goes right here.
• 00:27 Well, we can have multiple comparison statement.
• 00:30 We can do as many as we want.
• 00:31 And we'd string them together with a bit of logic.
• 00:34 And we do and/or, so and is just the and sign double,
• 00:39 or is just double pipes, up right pipes.
• 00:43 So let's go, and,
• 00:51 Or, so what's the difference between these two?
• 00:53 Well, let's just write something.
• 00:56 Let's say, lets change this to name and name equals Bill.
• 01:02 Hello John and Bill.
• 01:05 What do we have going on here?
• 01:06 So we have this conditional statement and this conditional statement.
• 01:09 And in order for this whole thing to evaluate into true,
• 01:13 both of these have to be true, because and means both conditions have to be met.
• 01:18 So if we save this and run it and I type in John, it says, I don't know you because
• 01:23 in order for this to be true, the name has to be John and Bill and that's impossible.
• 01:29 You can't have two names that are equal, right?
• 01:31 Well, in this case, we can use the or.
• 01:34 And with or, only one of these has to be true.
• 01:38 Either this has to be true, or this has to be true, in order for
• 01:42 this to get executed.
• 01:44 Otherwise, this gets executed.
• 01:46 So, save our program, run it again into your name, John.
• 01:50 Hello, John and Bill, run it again type in Bill.
• 01:54 Hello, John and Bill, run it and again, type in Mary.
• 01:57 I don't know you, because Mary is not John or Bill.
• 02:00 So this is very useful, you're going to use this a lot and you can keep going,
• 02:05 you can keep stringing these together, name equals Tim,
• 02:08 doesn't really matter, have as many as you want.
• 02:11 And you sort of have to decide whether and or or is more appropriate,
• 02:15 just based on whatever you're trying to do with your program.
• 02:19 So you might be thinking, well, what would we ever use and for?
• 02:23 Well, let's come up here to change this to number, change this to number.
• 02:31 And if we change this to, if number equals 41 and
• 02:35 number greater than 45, right, so one last thing we need to do.
• 02:41 Remember get stands for get string and we're dealing with integers now.
• 02:45 So we need to convert this to an integer and we already know how to do this.
• 02:48 We learned this a couple of videos ago, we use our to_i or 2 integer method.
• 02:54 So we save this, come back and run it.
• 02:56 And if we type in 41, it says I don't know you because the number is 41 and
• 03:01 that obviously equals 41, but it doesn't also end up being greater than 45.
• 03:05 And with and both of these things have to be true.
• 03:08 Now we can change this around a little bit, we can say greater than 41 and
• 03:12 greater than 45.
• 03:13 Save it and run it again, and type in say 99, 99 is greater than 41,
• 03:18 it's greater than 45, so it says Hello John and Bill.
• 03:21 Both of these evaluated to true.
• 03:23 We could come back and try it again and go say 43.
• 03:27 I don't know you because 43 is greater than 41, but
• 03:30 it's not also greater than 45.
• 03:32 So there are definitely reasons why you would want to use double and or double or.
• 03:37 Double and is often used with numbers and things like that.
• 03:39 But anyway, those are multiple conditionals,
• 03:41 multiple comparison operators, very useful.
• 03:44 In the next video will look at string manipulation.

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