For more information, please see full course syllabus of Introduction to PHP

For more information, please see full course syllabus of Introduction to PHP

### Expression & Operators

- An
__expression__is anything in PHP that has a value. - An
__operator__takes one or more expressions, called*operands*, and performs some operation on them to yield another expression. - Operators can be divided according to how many values they operate on:
*unary operators:*single value*binary operators:*two values*ternary operators:*three values

__Assignment operators__*(=, =>)*are binary operators used to assign the value of one expression to another expression .- There are
__arithmetic operators__for addition, subtraction, multiplication, division, and negation. There is also the*modulus (%)*operator used for getting the remainder of a division operation. - The
__increment/decrement operators__are used to increment or decrement their operand by one. They come in both*pre*and*post*forms. - The
__concatenation operator__*(.)*is used to combine two strings into one. - PHP provides
__combined assignment operators__for all of the binary arithmetic operators, as well as the concatenation operator. - Operators have both a
__precedence__and__associativity__. - When an expression contains multiple operations, the operations with higher
*precedence*are completed first. If an expression contains two operations of equal*precedence*, then the*associativity*of the operations determines which operation is completed first. - Additional Resources:

### Expression & Operators

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

- Intro
- Lesson Overview
- Expressions
- Operators
- Assignment Operators
- Arithmetic Operators
- Increment/Decrement Operators
- Combined Assignment Operators
- String Operators
- Precedence & Associativity
- Precedence & Associativity
- Expression Containing Multiple Operations
- Expression Containing Two Operations of Equal Precedence
- Using Parentheses to Force Precedence
- Precedence & Associativity Review
- Homework Challenge

- Intro 0:00
- Lesson Overview 0:10
- Lesson Overview
- Expressions 0:41
- Expressions Definition
- Example: Literals
- Example: Variables
- Operators 1:44
- Operators Definition
- Unary, Binary, and Ternary Operators
- Assignment Operators 2:52
- Assignment Operators
- Array Assignment Operator
- Arithmetic Operators 6:15
- Operators for Common Arithmetic Operations
- Modulus Operator
- Arithmetic Operators Example
- Increment/Decrement Operators 10:48
- Increment/Decrement Operators
- Pre- and Post- Increment/Decrement
- Coding Example
- Combined Assignment Operators 16:44
- Combined Assignment Operators
- Combined Assignment Operators Examples
- Coding Example
- String Operators 20:28
- Concatenation Operator, String Variables, and String Literals
- String Operators Example
- Precedence & Associativity 23:40
- Precedence & Associativity
- Expression Containing Multiple Operations
- Expression Containing Two Operations of Equal Precedence
- Using Parentheses to Force Precedence
- Precedence & Associativity Review
- Homework Challenge 31:08
- Homework Challenge

### Introduction to PHP

### Transcription: Expression & Operators

*Hello, and welcome back to Educator.com's Introduction to PHP course.*0000

*In today's lesson, we are going to be covering what are known as expressions and operators.*0005

*Specifically, we are going to be going over what expressions are and what operators are.*0012

*Then, we are going to go through a number of different operators that are available (and operators are things like addition, subtraction, and so forth).*0018

*And so, we are going to have a couple of slides going over a number of different operators available in PHP.*0025

*We are also going to go over a topic known as precedence and associativity,*0031

*which is like rules that apply when you do multiple operations at the same time.*0036

*What is an expression? That is part of what the lesson is titled.*0042

*Well, in PHP, an expression is anything that has a value; so literals have values, variables have values--they are all considered expressions.*0046

*For example, here we have three different literals: an integer, a float, and a string.*0056

*Those, obviously, are literal values; they have a value; they are considered expressions in PHP.*0060

*Additionally, variables have values; you set values to them.*0066

*Here we have an example of three different variables; we have a regular variable, an indexed array, and an associative array.*0070

*All of those have values, and they are considered expressions in PHP.*0080

*In this lesson, we are also going to be learning about operations, which are expressions in themselves, which means they have a value.*0084

*And then, in other lessons, we are going to be learning about constants, functions, and objects, all of which are expressions, as well.*0092

*And again, "expression" is just a synonym for something that has a value.*0099

*Operators work on expressions; an operator will take one or more expressions or values, which are referred to as operands,*0105

*which you may remember from your algebra days.*0116

*It performs an operation on those two expressions, those two operands, to yield another value for another expression.*0119

*The operators can be divided into categories, based on the number of operands they work on.*0128

*The ones that you are probably most familiar with would be something like an addition; you have 5+1.*0133

*It is what is called a binary operator; it has two operands--it has the 5 and the 1 that it operates on to yield a value.*0138

*In PHP, there are a couple of what are known as unary operators; and they are operators that work on a single value.*0148

*The majority of the operators we will see are binary operators for things like addition, subtraction, and multiplication.*0155

*PHP has one operator that has three values, known as a ternary operator.*0162

*But the majority of the operators are all binary.*0168

*The first operator we are going to specifically talk about is the assignment operator, and this is something we have already been using in our code.*0174

*We have already been using an operator, and maybe didn't even realize it.*0182

*An assignment operator is a binary operator, and as you know, it is used to assign the value of something to a variable, for example.*0186

*Basically, what that means in operator parlance: it is assigning the value of one expression to another expression.*0195

*For example, with the assignment operator (which we know is the equal sign), we have this expression here, 98.6, a float,*0204

*and we have this expression over here, bodyTemp, the variable.*0211

*The assignment operator says "Take this value and assign it to the variable on the left."*0215

*We have two expressions there.*0225

*Also, we have seen the array assignment operator, which is the equal sign followed by the greater than.*0228

*We have seen that in associative arrays where we have a key, and the way we associate a value in this case...*0235

*maybe Sunday it was 75 degrees; we associate the number with it using the array assignment operator.*0241

*And again, it takes the expression on the right-hand side and assigns it to the expression on the left-hand side.*0247

*Now, because both of these operators (the equal and the array assignment operator) are operators,*0255

*and we learn that operators work on one or more expressions to yield another expression,*0262

*these operations that we have seen up here (let me erase this) actually have a value.*0268

*It may not seem like it does, because normally you have something like 5+1, and you know that you have two operands and it yields a value of 6.*0275

*Well, this--because it is an operator, it has two expressions; it is a binary operator; it actually has a value itself.*0284

*This whole operation itself is an expression and has a value.*0291

*For the assignment operator, the value of the operation is the value being assigned.*0296

*And the way this might seem more apparent is: let's say we want to set a and b both equal to 5.*0301

*We have an expression like this, which is a legal statement in PHP.*0315

*PHP, with assignment operators, evaluates the one on the right first.*0323

*So, what PHP is going to do is: it is going to take this operation; it is going to assign the value 5 to the variable b.*0327

*And the value that that expression yields (which, for the assignment operator, is the value being assigned) is 5, is going to be assigned to a,*0336

*which makes sense, but it is essentially as if we had written it like this--if we had done it explicitly,*0346

*because when we assigned the value of a to the value of the assignment operation b=5, a gets assigned the value of 5.*0362

*There are arithmetic operators in PHP, as in most programming languages; and they have operators for all of the different typical arithmetic functions.*0376

*There is an addition operator and a subtraction operator.*0387

*You can do multiplication and division; and in PHP, like most programming languages, the multiplication operator is an asterisk.*0390

*So, if you want to multiply two numbers together, you would write it like...5 times 5 would look like that.*0400

*And the division operator is a forward slash; and so, if you want it to say 6 divided by 3, you would write it like this.*0408

*These four are all binary operators: addition, subtraction, multiplication, and division.*0418

*There is also the negation operator, which is a unary operator; that just takes the value of its operand and returns the negative version of it.*0425

*For example, if we have a=-5, this minus sign is the negation operator; it is saying to take the value of its lone operand, 5,*0436

*make it negative, and then the expression of value that that operation yields is -5, and so -5 is what is going to get set to a.*0452

*There is also another arithmetic operator known as the modulus operator, which is specified by the percent sign.*0463

*It is not as well known, but what it does is: it is basically a remainder function, so when you divide your numbers, it provides the remainder.*0471

*For example, if we have 7, modulus operator, 3, the result is going to equal 1; and the reason for that is:*0480

*if we divide 7 by 3 (go back to our elementary school math days), and we get 1, the remainder is 1.*0487

*And so, that is what this function outputs; that is a function to output remainders.*0499

*Let's take a look at a little code to demonstrate some of the different operators, which we will be able to look up from the Educator website,*0505

*basically just showing all of the different operators in action.*0515

*We are going to look at the HTML version of the code, because it's prettier and easier to look at.*0519

*For the addition operator, it is simply: as a binary operator, you take a value on the left and a value on the right.*0526

*It adds them together, and the result is, in this case, assigned to the variable a.*0532

*Here, if we have num=1, and then we add 1 to it, it is going to equal to, and a gets equal to 2.*0538

*All of the other arithmetic operators work intuitively the same sort of way.*0545

*For subtraction, if we have num set to 5, and we subtract 1 from it, the result of this operation is going to be the expression or value 4,*0549

*so a is going to get set to the value of 4.*0559

*And so on for multiplication and division: 2 times 2 equals 4; 6 divided by 3 equals 2; this is fairly intuitive.*0562

*The negation operator, which, as we mentioned before, is a minus sign, which is the same as the subtraction operator--*0570

*the way it is determined what it is going to be used as is the context it's in.*0577

*If it has two operands, it is treated as a binary operator, which means it's a subtraction operation.*0580

*Down here, it has one operand, the num variable; and so, this operator, the negation operator (let's blow this up a little bit) here--*0588

*the minus sign--says "Take the value of my one operand, num; negate it, and then set it equal to a."*0598

*So, in this case, a is going to be equal to -1.*0608

*And down here, we have this same modulus operation we had shown on the previous slide, 7%3.*0611

*That results in a remainder...when you divide 3 into 7, you get a remainder of 1, so a, in this case, is going to equal 1.*0621

*Just one thing to note is that the equation 7%3=1 is spoken "seven mod three equals one"; that is how you say it.*0627

*Like here, you would say, for division, "five divided by five equals," if it was a modulus operator, you would say, "seven mod three."*0636

*And so, that is how you speak it.*0645

*There are also what are known as the increment and decrement operators; what these operators do is:*0650

*they are unary operators--they operate on one value--and they increment or decrement the value of their operand by 1.*0656

*For example...first of all, they are represented by two plus signs and two minus signs together; this is the increment operator, and this is the decrement operator.*0665

*For example, we have variable i=0; right now, at the end of this statement, the value of i is equal to 0.*0678

*Now, we are going to perform the increment operation; we take the variable i, and we prepend it with the ++ operator,*0687

*the increment operator, which says, "Take my operand and increment it by one."*0697

*So, because i was equal to 0, and we have incremented by 1, at the end of this operation, i=1.*0704

*Likewise, for the decrement operator, it does the opposite: it subtracts 1; so this says, "Take the value of i and subtract 1 from it."*0711

*And again, that is two minus signs.*0721

*And so, because i previously was one, and we decrement it, i is now equal to 0.*0722

*There are kind of two operations going on at once here: i++, which...we will see there are actually two forms of the increment and decrement operators...*0728

*there is a pre form and the post form; this is the post form; they essentially mean the same thing, as far as incrementing or decrementing goes.*0740

*This says, "Increment the value of i."*0746

*It is essentially equal to if we had written the statement i=i+1; so, it's kind of an addition operation (we take the value of i; we add 1 to it),*0749

*and then an assignment operation, where we assign it back into itself.*0759

*Now, as mentioned, there is a pre form and a post form, and that is...either the operator goes before the variable, or it goes after the variable.*0764

*What that does is: because this is a combined operator of an addition and an assignment, whether you do a pre operator or a post operator*0776

*determines what value is yielded by this operation, because we know operations take one expression,*0784

*perform some operation on it, and yield another expression.*0793

*Well, with the pre increment operator, the value of the expression ++j is the value of j after it has been incremented.*0796

*So, if we assume j is 0 to start off with, and then we use the pre increment operator and set it equal to 1,*0805

*j is going to be equal to 1, because it has been incremented; and num is also going to be equal to 1.*0813

*Now, if instead we used the post increment version, where we have the operator after the variable name,*0818

*with the post increment operator, the value of the operation is the value of the operand before it is incremented.*0826

*So, right now, j is equal to 1 from the previous line where we incremented 0 to 1, the value of this operation,*0835

*because it's a post decrement, is j before it gets incremented.*0843

*So, num2 is actually going to get set to the value of j beforehand, which is 1.*0848

*So, num2 is going to equal 1; then j gets incremented, and j equals 2.*0853

*It is two different ways of using those operators.*0859

*Typically, you don't see the post one as often; typically you see the pre increment one, because it's a little less confusing.*0864

*When you use the post increment operator, I personally don't like to use it in my code, because it makes things a little less intuitive.*0874

*It adds some complexity to your code, because you have to think, "Well, is this setting the value before I've incremented it, or after it?"*0882

*So, in general, you don't see the post operators that much.*0888

*The thing that we will be using these operators for, mostly, is when we get to loops, which are ways to repeatedly go over lines of code.*0894

*Basically, they use a counter, and we use these pre increment operators*0904

*to continually add one to the counter each time it goes through the loop, for example.*0909

*If we look at another page that demonstrates some of these operations, we can see some of the same things that we went over here.*0915

*We have a variable num=1, and we pre-increment it; the value of num is going to be incremented, so num is going to be equal to 2.*0924

*Then, that value is going to be set to a, so a is going to be equal to 2.*0933

*We reset the value of num to 1, and then we set a equal to the value of the post increment operation on the variable num.*0937

*Well, the value of the post increment operation is the value of the variable before it's incremented,*0947

*so a is going to get set equal to num, which here is 1, so a is equal to 1.*0952

*Then, num is going to be incremented, so num equals 2.*0956

*So here, in this one, a and num end up having the same value at the end of this statement; here they have different values.*0959

*This, likewise, applies for the decrement operators, as well.*0967

*So, for example, if we have num=1, and we do a pre decrement on it, both a and num end up having the value of 0.*0970

*Now, with the post decrement operator, it's just like with the post increment operator.*0981

*The value of this operation is the value of num before it's decremented, so a is going to be equal to 1, because that is what num is set to.*0985

*And then, after num gets decremented, num gets set to the value of 0.*0995

*Those are the increment and decrement operators.*1000

*There are also what are known as combined assignment operators, kind of like what we just saw with the increment operator.*1006

*PHP has them for each of the different arithmetic functions, so they each have the corresponding combined assignment operator.*1013

*For example, the addition combined assignment operator is a + followed by an equal sign.*1022

*This is the one for subtraction, multiplication, division, and modulus.*1026

*Basically, it is kind of like when we had i++, we said that was the same as if we did i=i+1; that is kind of how these combined assignment operators work.*1031

*So, if we have num+=10, it is the same as saying "num is equal to the value of num, plus 10..."*1050

*What it does is adds 10 to whatever num is, and then reassigns the value to that variable.*1063

*It is kind of like the increment operator, except that here we have 10, and the increment operator always increments (or decrements) by 1.*1072

*Here, with the += operator, we can add however much we want to the variable.*1080

*This assignment is equivalent to this; and again, it's a combined assignment operation, because the first thing you have*1089

*is an addition operation that occurs: you take the number, and you add 10 to it.*1095

*The result of that--the value of that operation--is then assigned back into num.*1099

*Here are some more examples: if we start off with num=10, and then we do num+=10, at the end of this statement,*1104

*the value num is going to be equal to 20, because we have taken num's value, which was 10, added 10 to it, and reassigned it back to num.*1112

*Now, if we use, for example, the multiplication combined assignment operator, this says,*1122

*"Take num, multiply it by 5, and then store the result of that back in num."*1128

*So, up here, num was equal to 20 at the end of this statement, so 20 times 5 is 100; so at the end of this operation, num equals 100.*1134

*A similar pattern follows; if we do num and then use the combined division assignment operator,*1144

*it is going to say, "Take the value of num (which is 100), divide it by 4, and set that back to be the value of num."*1151

*So in this case, num equals 25.*1156

*And then, the modulus operator--the same way: it is going to say, "Take the value of num (which is 25); mod it with 6;*1158

*and store the result back in num," and just to show the mod operator again: you do...6 goes into 25; we get a remainder of 1.*1166

*So, that is why this is equal to 1.*1176

*We have a page that demonstrates this as well; and this page kind of echoes what we have just done.*1180

*It shows how all of these look in code; we have a variable name, and then here, we have done the += operator.*1188

*That is going to result in the value of num, incremented by 10.*1196

*Here we have the -= operator, which is going to say "subtract 10 from the previous value of num and set num to that value."*1202

*So, num is going to be equal to 1 here.*1208

*Here, we see the multiplication combined assignment operator again; so it is going to say, "Take num and multiply it by 20."*1211

*So, num is going to be equal to 20.*1215

*Here we divide it by 4; num is equal to 5; and then, mod...you end up with num=1.*1217

*Now, we are going to talk about string operators: there are two string operators.*1230

*Well, it's one string operator known as the concatenation operator, and then it has a combined assignment version, just like the arithmetic operators.*1236

*The concatenation operator is simply a period, and it is an operator that is used to combine, or concatenate, two strings together.*1245

*It is a binary operator; so here we have the binary operator, the period.*1256

*And it has two operands: on one side is hello--the string literal hello; on the other side is world.*1260

*And this operator says to take these two values, these strings and concatenate them together, and the result is the string concatenated.*1268

*So, the message (at the end after this concatenation operation occurs) becomes the literal "hello world" where they are all combined into one string.*1277

*You can use this with both literals and variables.*1292

*For example, we could create a variable called day and set it equal to Monday, and then we could create a variable that's going to hold a message.*1295

*We started off with a string literal, "Today is", and that is one operand of the concatenation operator.*1303

*The other operand we can set to the variable day, and what that is going to do is concatenate these two strings together.*1311

*It is going to take "Today is" and combine it with the string that day represents, which is Monday,*1318

*and output that as one string, and set it equal to message.*1324

*So, at the end of this, message is going to be equal to "Today is Monday."*1327

*Now, just like the other operators, the arithmetic operators, there is a combined assignment version for this one, too.*1333

*That is this here--the .= ; and basically, it is just like how the arithmetic ones work in that, if we have begin.=end,*1339

*that is saying, "Take the variable being, concatenate it with end (the operand on this side of the operator), and then assign that back into begin."*1349

*Let's take a look at a page demonstrating this.*1364

*This demonstrates the two examples that we saw: we have a string hello, and what we have done is saved it in message.*1370

*And then, we have taken the variable message, which is equal to the string hello, and we have concatenated it with the string literal world.*1380

*So, at the end of this operation, message is equal to the string literal hello world.*1388

*We could also do the same operation using a combined assignment operator, where if we set message equal to hello,*1394

*as we did up here, instead of having to write a full expression like this, we can just do .=world.*1400

*What that is going to do is just concatenate the world string to the string that message already is, which is hello.*1406

*And so, again, at the end of this, message is going to be equal to hello world.*1412

*Now, one thing I want to talk about to finish up the lecture is a topic known as precedence and associativity.*1421

*Basically, all operators have assigned to them a precedence and an associativity.*1428

*What those are for is when you have multiple operations occurring in the same statement.*1433

*For example, this statement right here has two operations: it has a multiplication operation, and it has an addition operation.*1438

*When PHP sees that, it has to have rules as to which operation it proceeds with first.*1449

*It could go left to right and say, "OK, I'm going to do 5 times 6 first; the value of that is 30, plus 2, and the value is equal to 32."*1454

*It could go the other way and say, "6+2 is 8; 8x5 is 40."*1463

*Well, the rules in PHP are that multiplication has a higher precedence than addition.*1469

*So, when those two operators occur in the same statement, the one with the higher precedence, multiplication, gets completed first.*1475

*It is sort of the same thing as if we had written this in parentheses here.*1482

*The value of this expression is actually 32, and not 40.*1485

*And actually, if you go...I have a link on the homework challenge to the PHP website and the PHP manual;*1492

*there is an operator precedence page, and what it does is: it lists all of the different operators, and most of these we haven't seen yet,*1499

*which you can just ignore for now.*1505

*And it ranks them in decreasing precedence; for example, as you can see, multiplication and division are at a higher level than addition and subtraction.*1507

*So, as we can see in the last example, multiplication happened first.*1521

*Now, what happens then, and the way this chart works, is that everything on the same line has the same precedence.*1527

*So, what if you have two operations that are occurring in the same statement where both operators have the same precedence?*1533

*Well, then you defer to what is known as associativity.*1541

*What that does is determines, "If you have operators in the same precedence, do they get evaluated left to right or right to left?"*1546

*So, go back and look at the slide here: the multiplication sign and the modulus operator both have the same precedence.*1554

*In order to decide which one gets operated on first, PHP defers to the rules of associativity.*1566

*The associativity for these operators is left, which means they get operated from left to right fashion.*1572

*So, what is going to happen is: 3 times 3 is first going to get multiplied, and then it's going to be mod-ed with 2,*1578

*as opposed to the other way around, 3 mod 2 times 3.*1586

*The result of this is actually 1 and not 3, because 3 times 3 is 9, and if you divide it by 2, the remainder is equal to 1,*1594

*as opposed to 2 goes into 3, remainder of 1, 1 times 3 is 3.*1604

*This demonstrates left associativity.*1609

*Now, as we saw in a previous slide, the assignment operator is right associative; so when we have a=b=5, this statement contains two assignment operations.*1614

*It has two assignment operators; they have equal precedence; so how does PHP decide which operation gets performed first?*1630

*Well, the associativity rules say the assignment operator is right associative, so the right one is going to get performed first,*1639

*and then move to the left, so then the left one will be operated.*1646

*As we saw before, b=5 gets operated first; that assignment operation occurs,*1651

*and we know that the value of an assignment operation is the value that was assigned.*1655

*This one occurs first, and then that value was assigned into a; so the assignment operator is an example of a right associative operator.*1661

*Now, one other thing that you can do, which you may remember back in math days, is force precedence using parentheses.*1672

*So, as up here, we had seen that, since multiplication has a higher precedence, it gets evaluated first, so we have 5x6 is 30,*1680

*and we add 2 to get 32; if we wanted to do reverse and add 6+2 first, and then multiply times 5,*1688

*we can force the precedence by adding the parentheses.*1695

*What that is going to do is tell PHP, "let me do what is in parentheses first: 6+2 is yielding 8; then multiply that times 5," so that is how we get 40 here.*1698

*The same way for this other operation: because, in this case, the multiplication and modulus operator have the same precedence,*1707

*associativity determines which operation occurs first, and associativity for these operators is left, so multiplication would go first.*1716

*By adding the parentheses here, we are saying we want to do this operation first; so 3 mod 2 has a remainder of 1, so it's equal to 1.*1725

*1 times 3 equals 3; so now, the value of the equation changes.*1733

*I have some examples of that, as well.*1740

*Basically, this is just a review of what we talked about; and we talked about precedence, saying that operations with higher precedence execute first.*1748

*In this case, which is a little bit different and shows the importance of precedence (because normally we read left to right,*1758

*and we would think this operation occurred first), in this example, multiplication has a higher precedence, so 2x3 is executed first,*1766

*which is equal to 6+5, is equal to 11; not 21, which would be the case if we added 5 and 2 and got 7 and multiplied it times 3.*1773

*Now, this example down here demonstrates associativity; again, the modulus operator and the multiplication operator*1782

*both have the same precedence, so the rules of associativity apply,*1788

*which say the leftmost operation gets performed first, and then it proceeds to the right.*1792

*In this case, 11 mod 3...3 goes into 11 three times with a remainder of 2, so we get 2 times 2; this results in num being equal to 4.*1797

*That is not 5, as if we had done this instead--if we had done the multiplication operation first.*1809

*For example, if these were right associative operators, we would have 3 times 2 is 6; 11 mod 6 is equal to 5.*1817

*And so, you just want to note that these have left associativity;*1827

*and as we talked about before, some operators, like the assignment operator, have right associativity.*1830

*And again, you can use parentheses to force precedence; so these examples that were shown above are now shown with parentheses,*1836

*to have them operated a different way: in this case, we can get the value to equal 21 by forcing the addition operation,*1843

*the lower-precedence operation, to happen first.*1849

*And then here, whereas the multiplication has the same precedence as the modulus operation,*1852

*but those operators are both left associative, we can force the right operation to occur first with parentheses.*1859

*For today's homework challenge, what I would like you to do is to go out and take a look at this link.*1870

*It's on the PHP manual, and what it does is shows you all of the different operators that are available in PHP.*1874

*And you can, like I said before, ignore the ones that we haven't covered yet, but you can see where all the different operators rank,*1882

*because when we eventually start writing arithmetic functions, and doing calculations, it is going to be important to know how they work.*1889

*And so, here, you can just see how the precedence works, and you can see that multiplication and division and modulus are higher up*1897

*in precedence than the plus or the minus or, in fact, the concatenation operator, as well.*1904

*That ends today's lesson; thank you for watching Educator.com--I look forward to seeing you next time.*1911

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