Operators

This video was created by Dani Krossing

Operators are symbols that take one or more values or expression and yields another value. There are many categories of operators, but for now we will cover the following:

• Arithetic Operators
• Assignment Operators
• Comparison Operators
• Logical Operators
• Incrementing/Decrementing Operators
• String Operators

Arithmetic Operators

Arithmetic operators are used to perform basic arithmetic, including addition, subtraction, multiplication, and division.

Operator	Name	Example	Result
+	Addition		Sum of $a and $b
-	Subtraction		Difference of $a and $b
*	Multiplication		Product of $a and $b
/	Division		Divides $a by $b
%	Modulo		Remainder of $a divided by $b

<?php
  $a = 4;
  $b = 3;

  echo $a + $b; // 7
  echo $a - $b; // 1
  echo $a * $b; // 12
  echo $a / $b; // 1.3333333333
  echo $a % $b; // 1
?>

Try it yourself on Repl.it

Assignment Operators

Assignment operators are used to assign a value to a variable. The most common assignment operator is the =. There are also combined operators which are used to perform arithmetic, array unions, and string concatenations while also assigning the value to a variable.

Operator	Name	Example	Result	Equivalent
=	Basic assignment		$a will be set to the value of $b
+=	Addition assignment		$a will be set to the difference of $a and $b
-=	Subtration assignment		$a will be set to the sum of $a and $b
*=	Multiplication assignment		$a will be set to the product of $a and $b
/=	Division assignment		$a will be set to the division of $a by $b
%=	Modulo assignment		$a will be set to the remainder of $a divided by $b
.=	String concatentation assignment		$a will be set to the concatenation of $a and $b

Comparison Operators

Comparison Operators are used to compare two values. When comparing values of different data types, for example, a string and a number, PHP will attempt to convert the string to a number first and then do the comparison.

Operator	Name	Example	Result
==	Equal		TRUE if $a is equal to $b in value
===	Identical		TRUE if $a is equal to $b in value and data type
!=	Not Equal		TRUE if $a is not equal to $b in value
!==	Not Identical		TRUE if $a is not equal to $b in value and data type
<	Less than		TRUE if $a is less than $b
>	Greater than		TRUE if $a is greater than $b
<=	Less than or equal to		TRUE if $a is less than or equal to $b
>=	Greater than or equal to		TRUE if $a is greater than equal to $b
<=>	Spaceship		Returns 0 if $a is equal to $b Returns 1 if $a is greater than $b Returns -1 if $a is less than $b

<?php
  $a = 4;
  $b = 3;
  $c = 1;
  $d = 20;

  var_dump($c == 1);    // bool(true)
  var_dump($c == "1");  // bool(true)
  var_dump($c === 1);   // bool(true)
  var_dump($c === "1"); // bool(false)
  var_dump($c != 1);    // bool(false)
  var_dump($c != "1");  // bool(false)
  var_dump($c !== 1);   // bool(false)
  var_dump($c !== "1"); // bool(true)

  var_dump($a > $b);    // bool(true)
  var_dump($c < $b);    // bool(true)
  var_dump($d < $d);    // bool(false)
  var_dump($d <= $d);   // bool(true)
  var_dump($d >= $b);   // bool(true)

  var_dump($a <=> $b);  // int(1)
  var_dump($a <=> $d);  // int(-1)
  var_dump($a <=> $a);  // int(0)
?>

Try it yourself on Repl.it

Logical Operators

Logical Operators are used to combine and make more complex expressions.

Operator	Name	Example	Result
!	Not		TRUE if $a is not TRUE
&&	And		TRUE if both $a and $b are TRUE.
`		`	Or

Caution

It is also possible to use and and or in place of && and ||. But these operators have different precedence and can result in unexpected results. Review the Logical Operators documentation for more information.

<?php
  $a = 4;
  $b = 3;
  $c = 1;
  $d = 20;

  // this condition will be FALSE
  if (($a > $b) && ($c > $d)) {
    echo "a is larger than b AND ";
    echo "c is larger than d"; 
  }

  // this condition will be TRUE
  if (($a > $b) || ($c > $d)) {
    echo "a is larger than b OR ";
    echo "c is larger than d"; 
  }

  // setting e if it is not set
  if (!isset($e)) {
    $e = 200;
  }
  echo $e;
?>

Incrementing/Decrementing Operators

Incrementing/Decrementing operators supports pre- and post-increment and decrement operators.

Operator	Name	Example	Result
++	Pre-increment		Increments $a by one, then returns $a
++	Post-increment		Returns $a, then increments $a by one
--	Pre-increment		Decrements $a by one, then returns $a
--	Post-increment		Returns $a, then decrements $a by one

String Operators

PHP only supports two String Operators, the concatenating assignment operator (.=) mentioned above, and the concatenation operator, which is used to combine strings.

<?php 
$a = "Hello ";
$b = "World"; 

echo $a . $b; // Hello World
?>