Using PHP is_object Function to Check if a Variable Is an Object

In PHP, variables can hold many types such as integers, strings, arrays, booleans, and objects; objects encapsulate data and methods. To determine whether a variable is an object, PHP provides the built-in is_object function.

The function signature is bool is_object ( mixed $var ) , where $var is the variable to test and the function returns true if $var is an object, otherwise false .

The article presents a practical example that creates an empty stdClass object and an array, then uses is_object to check each variable, outputting appropriate messages.

// Create an empty object
$obj = new stdClass();

// Define an array
$arr = array(1, 2, 3);

// Check if variable is an object
if (is_object($obj)) {
    echo "Variable is an object";
} else {
    echo "Variable is not an object";
}

if (is_object($arr)) {
    echo "Variable is an object";
} else {
    echo "Variable is not an object";
}

The example demonstrates that the check returns true for the object and false for the array, confirming that is_object only identifies objects and cannot be used for arrays.

It also notes that although arrays and objects share some similarities, they are distinct data types, and is_object should not be used to test for arrays.

In summary, the is_object function offers a convenient way to verify object types in PHP, helping developers avoid type‑related errors.