What is the difference between “!==” and “==!” in PHP?
Answers (2)
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!== Operator: It is called as non-identical operator.
Returns true if operands are not equal, or they are not of the same type.
Syntax:
$a !== $b
Where $x and $y are the operands.
Examples 1:
$a = true
$b = false
$a !== $b
Output: true
Examples 2:
$x = array('hello', 'world', 'welcome');
$y = array('eat', 'work', 'sleep');
// return true
var_dump($x !== $y);
==! Operator: It is nothing but it can be further written as ==(!operand)
Returns true or false depending on operands. Both the operators return the Boolean values either true or false.
Syntax:
$a ==! $b
Examples 1:
$a = true $b = false $a ==! $b
Output: true
Examples 2:
$x = array('hello', 'world', 'welcome');
$y = array('eat', 'work', 'sleep');
// return false
var_dump($x ==! $y);
!== Operator: The non-identical operator is what it’s called. If the operands are not equal or of the same type, it returns true.
Syntax:
$x !== $y
Where $x and $y are the operands.
==! Operator: It’s nothing, but it can also be expressed as ==(!operand), which returns true or false depending on the operands. Both operators produce either true or false boolean values.
Syntax:
$x ==! $y
Example 1: This program uses both operands and returns the output.
<?php // PHP program to demonstrate // !== and ==! operator // Declare variables $x = true; $y = false; $z = true; // Using !== operator echo "Using !== operator\n"; // Is $x not equals to $y // so true returned var_dump($x !== $y); // Is $x not equals to $z // so false returned var_dump($x !== $z); // Is $y not equals to $z // so true returned var_dump($y !== $z); // Using ==! operator echo "\nUsing ==! operator\n"; // Is $x equals to (!$y) // so true returned var_dump($x ==! $y); // Is $x equals to (!$z) // so false returned var_dump($x ==! $z); // Is $y equals to (!$z) // so true returned var_dump($y ==! $z); ?>
Output:
Using !== operator bool(true) bool(false) bool(true) Using ==! operator bool(true) bool(false) bool(true)
Program 2:
<?php // PHP program to demonstrate // !== and ==! operator // Dsclare associative array $x = array( "1" => "Geeks", "2" => "for", "3" => "Geeks" ); $y = array( "5" => "Tony", "6" => "Captain", "7" => "Thor" ); // Union of $x and $y $z = $x + $y; // Using !== operator echo "Using !== operator\n"; // Is $x not equals to $y // so true returned var_dump($x !== $y); // Is $x not equals to $z // so true returned var_dump($x !== $z); // Is $y not equals to $z // so true returned var_dump($y !== $z); // Using ==! operator echo "\nUsing ==! operator\n"; // Is $x equals to (!$y) // so false returned var_dump($x ==! $y); // Is $x equals to (!$z) // so false returned var_dump($x ==! $z); // Is $y equals to (!$z) // so false returned var_dump($y ==! $z); ?>
Output:
Using !== operator bool(true) bool(true) bool(true) Using ==! operator bool(false) bool(false) bool(false)
