PHP - Logical negation: !

The logical negation operator is used to determine the oposite value. in our case: if input is true then output is false, and if input is false the result is true. In next table you can find all possibilities:

a	x
False	True
True	False

information about the table: a is input, x is result

!

Description

! par1

Used keywords: !

Input

par1 - Logical value

Output

Result - Logical value

Examples

PHP

In the source code you can find the equivalent of the above table, for easier orientation at the end of each line is a comment which shows the result.

$a1 = !false; // a1 = true
$a2 = !true; // a2 = false

PHP

Even one example in what situations we can use the operation logical negation:

!$a
!$b && true
!(10 >$a || $a<5)

PHP

Other pieces of example codes:

!$a

You can find it in the following collections: logical operators

Logical negation in another programming language:

Differences to: