Logic Operators

Quick reference

• 00:04 In the last video, we talked about increment operators.
• 00:07 In this video, I wanna talk about logic operators.
• 00:10 Logic operators go with conditional statements and comparison operators.
• 00:14 We haven't learned about conditional statements yet, so
• 00:16 it's kind of hard to see these in action.
• 00:18 In just a couple videos from now, we're gonna talk about conditional statements,
• 00:22 and then we'll be able to use all of these in more concrete ways.
• 00:24 So what's a logic operator?
• 00:25 When it comes to programming most of the time, your logic is gonna be and and or.
• 00:31 Let's just kind of play around with summaries.
• 00:33 Is 5 greater than 1?
• 00:35 Yes, it is.
• 00:37 And is 10 > 2, this is not
• 00:42 a real PHP statement, but to use and we actually just type the word and, or
• 00:47 we can also use this && sign, either of them will work with PHP.
• 00:53 So I'm just gonna type in and for now.
• 00:54 In order for this to evaluate true, both of these conditions have to be true.
• 00:59 This has to be true and this has to be true.
• 01:03 So, is it?
• 01:03 Is 5 > 1?
• 01:05 Yes. Is 10 > 2?
• 01:06 Yes, this is true.
• 01:09 Is 5 > 1 and 10 > 100?
• 01:14 5 is yes, greater then one and is 10 greater than a 100,
• 01:19 no 10 is not so this is false.
• 01:22 That's and, likewise, or
• 01:25 is 5 greater then 1 or 10 greater than 100.
• 01:32 For this to be true, either this one or this one has to be true.
• 01:38 If either of these are true, then it evaluates to true.
• 01:42 If both of them are true, it also evaluates to true, it's both or one or
• 01:46 the other.
• 01:47 So 5 > 1.
• 01:48 Yes.
• 01:49 10 > 100?
• 01:50 No.
• 01:51 This is false, but this is true.
• 01:53 And since only one of these has to be true, this evaluates to true.
• 01:58 Likewise, is 5 greater than 10, or 10 greater than 100?
• 02:04 5 is not greater than 10, so that's false.
• 02:06 10 is not greater than 100, so that's false.
• 02:09 Neither one of these is true.
• 02:11 So this whole statement evaluates to false.
• 02:14 And you can do this, double && sign.
• 02:18 That's the same thing, same thing for or, we can do those double pipe sign.
• 02:23 Either of these will work.
• 02:25 Those are logical operators.
• 02:26 There' s actually one more, it's called x or and for x or
• 02:30 to be true either those has to be true, but not both.
• 02:33 So if 5 > 10, x or
• 02:38 10 > 100, is this true?
• 02:44 5 is not greater than 10.
• 02:46 10 is not greater than 100 and neither of these is true, so this is false.
• 02:51 Let's try a different one.
• 02:52 Is 5 > 1x or 10 > 100.
• 02:57 Well, 5 is greater than 1.
• 02:59 10 is not greater than 100.
• 03:00 One of these has to be true, but the other one can't be true.
• 03:04 So, this is true.
• 03:05 And finally, one more example, is 5 > 1x or 10 > 1.
• 03:12 Well, 5 is greater than 1, that's true.
• 03:14 10 is greater than 1, that's true, but the statement is false.
• 03:19 Why? Because for x or
• 03:20 to be true, one of them has to be true, but the other one can't be true.
• 03:24 So only one of them can be true for the whole statement to evaluate true.
• 03:28 If your head is spinning don't worry about it.
• 03:30 You're not going to use x or very much.
• 03:31 These are just general things.
• 03:33 These are not actually how you use these in PHP.
• 03:35 We'll learn how to use them once we learn conditional statements.
• 03:38 A couple of videos from now, but this is the general logic behind it, and and or.
• 03:42 Very popular, cuz a lot of times you wanna evaluate two different things.
• 03:46 You wanna say is 5 > 1 and is 10 > 2.
• 03:49 When that's the case, you'll use these logic operators.
• 03:52 In the next video, we'll look at string operators.
• 03:54 That'll be our last operator to look at and we'll move on from there.

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