Assignment Operators

Quick reference

• 00:05 In this video I wanna talk about assignment operators.
• 00:07 Now assignment operators assign things to other things.
• 00:10 And we've actually already seen this when we talked about variables.
• 00:13 This var first name = John.
• 00:17 We are assigning John to the variable first name.
• 00:20 And we do it with this equal to sign.
• 00:22 So this equal to sign is an assignment operator.
• 00:25 Right, it assigns something.
• 00:27 The equals to sign is probably the most common assignment operator,
• 00:31 you're gonna see that all the time.
• 00:32 But there are a whole bunch of other ones, too, and
• 00:34 we're gonna talk about those in this video.
• 00:35 So what are some of those other ones?
• 00:41 Well you've got +=, we've got -=, we've got *=, we've got /=, we've got modulus =
• 00:45 and that's pretty much all the ones we're going to talk about in this video.
• 00:49 There are some other ones that are more esoteric and
• 00:51 you won't see very often but these are the main ones.
• 00:53 These do pretty much what you would expect them to do.
• 00:56 They do some math and they assign the answer to something else.
• 00:59 So like as you would expect this one adds an equals to.
• 01:02 This one subtracts an equals to, this one multiplies an equals to,
• 01:05 this one divides an equals to, and this one does a modulus equal to.
• 01:09 You may not be familiar with that one.
• 01:10 It's not one people are often familiar with.
• 01:12 But a modulus just finds a remainder.
• 01:14 Remember when you divided when you were like in fourth grade in grade school.
• 01:19 For instance, three goes into eight two times, with two remainder, right?
• 01:24 So that's what this modulus does it finds the remainder.
• 01:27 Like I said, we'll talk about math in a couple of videos from now.
• 01:30 But, for right now, let's just kinda look at this, and let's erase all this.
• 01:34 And let's go var myNumber =,
• 01:40 I don't know, 20, right?
• 01:44 So we use one of these assignment operators to go myNumber += 5, right?
• 01:51 So what do we think this is gonna do?
• 01:53 Well, we can do a document.write and then write out my number to the screen.
• 02:00 Save this and let's take a look at this.
• 02:03 And boom, the answer is 25.
• 02:04 So what it's doing is it's taking 20 and it's adding five to it and
• 02:08 then slapping the answer back into the variable.
• 02:10 So it would be sort of like if you went myNumber = myNumber + 5, right?
• 02:21 If we save this, come back and hit reload, we're gonna get the same answer 25.
• 02:25 But this is just a much shorter, easier, more elegant way to do that.
• 02:32 Right, basically that's all it is.
• 02:34 And it's the same thing with all the rest of these,
• 02:36 if we go -= 2 that would be 20- 5 so our answer is going to be 15.
• 02:41 If we go *= it's going to be, what, 100?
• 02:46 If we go /= it's going to be 4, and
• 02:50 if we go modulus = it's probably going to be 0, right?
• 02:54 Right, so we can change this around and go 11, right?
• 02:57 5 goes into 11 two times, with 1 left over.
• 03:00 'Cause 2 times 5 is 10.
• 03:02 11- 10 is 1.
• 03:03 So if we save this, it should be one.
• 03:05 Yup, there we go.
• 03:06 So assignment operators, very useful, we'll use these a lot for
• 03:10 a lot of different things and like I said, the equal to sign is probably going to be
• 03:13 the most common one that you're going to use.
• 03:14 You're always going to be assigning things to variables and
• 03:17 all kinds of other things, so it's just second nature.
• 03:20 But you'll actually use those other ones as well so
• 03:22 just sort of keep those in mind.
• 03:24 So that's all for
• 03:24 assignment operators and in the next video we'll talk about math operators.

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