What is the difference between == and === in PHP?

In PHP, the == (equality) and === (identity) are two different comparison operators used to evaluate equality between values. Here’s the difference between them:

1. == (Equality Operator):

• The == operator checks if two values are equal, regardless of their data types.
• It performs type coercion, meaning it tries to convert the values to a common type before comparing them.
• If the compared values are different data types, PHP will attempt to convert them to a common type based on certain rules. For example, when comparing a string and an integer, PHP will convert the string to an integer before performing the comparison.
• Example: $x == $y returns true if $x and $y are equal after type coercion, and false otherwise.

1. === (Identity Operator):

• The === operator checks if two values are identical, both in value and data type.
• It does not perform type coercion and requires both the value and data type to be the same for the comparison to be true.
• Example: $x === $y returns true if $x and $y are equal in value and data type, and false otherwise.

Here’s an example to illustrate the difference between the two operators:

$x = 5; // integer
$y = "5"; // string

var_dump($x == $y); // Outputs: bool(true), since "5" (string) is equal to 5 (integer) after type coercion
var_dump($x === $y); // Outputs: bool(false), since the data types are different (integer vs. string)

In summary, the == operator checks for equality after type coercion, while the === operator checks for identity, considering both value and data type. It is generally recommended to use === for precise comparisons to avoid unexpected results due to type coercion.