PHP count Function

last modified March 13, 2025

The PHP count function counts all elements in an array or properties in an object. It's essential for working with collections.

Basic Definition

The count function returns the number of elements in an array. It can also count public properties of an object when used with COUNT_NORMAL.

Syntax: count(Countable|array $value, int $mode = COUNT_NORMAL): int. The mode parameter can be COUNT_RECURSIVE for multidimensional arrays.

Basic count Example

This shows how to count elements in a simple array using the count function.

basic_count.php

<?php

$fruits = ['apple', 'banana', 'orange', 'grape'];
$count = count($fruits);

echo "There are $count fruits in the basket.";

This counts the elements in the $fruits array. The function returns 4, which we display in a formatted string.

Counting Multidimensional Arrays

Demonstrates counting elements in a multidimensional array with COUNT_RECURSIVE.

multidimensional_count.php

<?php

$matrix = [
    ['a', 'b', 'c'],
    ['d', 'e'],
    ['f', 'g', 'h', 'i']
];

$normalCount = count($matrix);
$recursiveCount = count($matrix, COUNT_RECURSIVE);

echo "Normal count: $normalCount\n"; 
echo "Recursive count: $recursiveCount";

COUNT_NORMAL counts only top-level elements (3). COUNT_RECURSIVE counts all elements at all levels (9 total). The second level counts are included.

Counting Object Properties

Shows how count behaves when used with objects and their properties.

object_count.php

<?php

class User {
    public $name;
    public $email;
    private $password;
    
    public function __construct($name, $email) {
        $this->name = $name;
        $this->email = $email;
        $this->password = bin2hex(random_bytes(8));
    }
}

$user = new User('John Doe', 'john@example.com');
$count = count($user);

echo "Public properties: $count";

Count only sees public properties (name and email). Private properties like password are not counted. The result is 2 public properties.

Empty Array Behavior

Demonstrates how count handles empty arrays and non-countable values.

empty_count.php

<?php

$emptyArray = [];
$count = count($emptyArray);

echo "Empty array count: $count\n"; 

$nullValue = null;
$count = count($nullValue);

echo "Null count: $count";

Empty arrays return 0. Non-countable values like null also return 0. For scalars, count returns 1 unless the value is null.

Counting with SPL Countable

Shows how count works with objects implementing the Countable interface.

countable_interface.php

<?php

class BookCollection implements Countable {
    private $books = [];
    
    public function add($book) {
        $this->books[] = $book;
    }
    
    public function count(): int {
        return count($this->books);
    }
}

$library = new BookCollection();
$library->add('PHP Guide');
$library->add('JavaScript Basics');
$library->add('Python Cookbook');

echo "Books in collection: " . count($library);

Objects implementing Countable can define their own counting logic. Here, count() uses the object's count() method. The result reflects the internal array size.

Best Practices

Type Checking: Verify countable types before counting.
Performance: Avoid COUNT_RECURSIVE on large arrays.
Objects: Implement Countable for custom collections.
Null Safety: Remember null returns 0, not an error.

Source

PHP Count Documentation

This tutorial covered the PHP count function with practical examples showing its usage for counting array elements and object properties.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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