PHP Operators

 There are following types of operator in PHP:

1. Arithmetic operators
2. Assignment operators
3. Comparison operators
4. Increment/Decrement operators
5. Logical operators
6. String operators
7. Array operators
8. Conditional assignment operators

Arithmetic operators:

+ Addition $x + $y Sum of $x and $y

- Subtraction $x - $y Difference of $x and $y

* Multiplication $x * $y Product of $x and $y

/ Division $x / $y Quotient of $x and $y

% Modulus $x % $y Remainder of $x divided by $y

** Exponentiation $x ** $y Result of raising $x to the $y'th power

Assignment operators:

x = y x = y The left operand gets set to the value of the expression on the right

x += y x = x + y Addition

x -= y x = x - y Subtraction

x *= y x = x * y Multiplication

x /= y x = x / y Division

x %= y x = x % y Modulus

Comparison operators:

== Equal $x == $y Returns true if $x is equal to $y
=== Identical $x === $y Returns true if $x is equal to $y, and they are of the same type
!= Not equal $x != $y Returns true if $x is not equal to $y
<> Not equal $x <> $y Returns true if $x is not equal to $y
!== Not identical $x !== $y Returns true if $x is not equal to $y, or they are not of the same                  type
> Greater than $x > $y Returns true if $x is greater than $y
< Less than $x < $y Returns true if $x is less than $y
>= Greater than or equal to $x >= $y Returns true if $x is greater than or equal to $y
<= Less than or equal to $x <= $y Returns true if $x is less than or equal to $y
<=> Spaceship $x <=> $y Returns an integer less than, equal to, or greater than zero,                 depending on if $x is less than, equal to, or greater than $y. Introduced in PHP 7.

Increment/Decrement operators:

++$x Pre-increment Increments $x by one, then returns $x

$x++ Post-increment Returns $x, then increments $x by one

--$x         Pre-decrement Decrements $x by one, then returns $x

$x--         Post-decrement Returns $x, then decrements $x by one

Logical operators:

and And $x and $y True if both $x and $y are true

or Or $x or $y True if either $x or $y is true

xor Xor $x xor $y True if either $x or $y is true, but not both

&& And $x && $y True if both $x and $y are true

|| Or $x || $y True if either $x or $y is true

! Not !$x True if $x is not true

String operators:

. Concatenation $txt1 . $txt2 Concatenation of $txt1 and $txt2

.= Concatenation assignment $txt1 .= $txt2 Appends $txt2 to $txt1

Array operators:

+ Union $x + $y Union of $x and $y

== Equality $x == $y Returns true if $x and $y have the same key/value pairs

=== Identity $x === $y Returns true if $x and $y have the same key/value pairs in the same order          and of the same types

!= Inequality $x != $y Returns true if $x is not equal to $y

<> Inequality $x <> $y Returns true if $x is not equal to $y

!== Non-identity $x !== $y Returns true if $x is not identical to $y

Conditional assignment operators:

?: Ternary $x = expr1 ? expr2 : expr3 Returns the value of $x.

        The value of $x is expr2 if expr1 = TRUE.

        The value of $x is expr3 if expr1 = FALSE

?? Null coalescing $x = expr1 ?? expr2 Returns the value of $x.

        The value of $x is expr1 if expr1 exists, and is not NULL.

        If expr1 does not exist, or is NULL, the value of $x is expr2.

        Introduced in PHP 7