How to use count function in php

Use the count() function to calculate the number of elements: Array: count([1, 2, 3]) returns the number of array elements. String: count("Hello World!") returns the number of characters. Object: An object that implements the Countable interface, such as SplObjectStorage, can use count() to count the number of elements. Iterable objects: You can use iterable objects such as SplObjectStorage to count the number of elements. Non-array, string, or iterable object variable: count() returns null.

How to use count() function in PHP

The count() function is used to count arrays in PHP , the number of elements of a string or object.

Syntax

count(variable)

where variable can be:

• Array
• String
• Object (implements the Countable interface)
• Any iterable object (for example, SplObjectStorage )

Usage

For arrays, the count() function returns the number of elements in the array:

$arr = [1, 2, 3, 4, 5];
$count = count($arr); // $count 为 5

For strings , The count() function returns the number of characters in the string:

$str = "Hello World!";
$count = count($str); // $count 为 12

For objects, the count() function only applies to objects that implement the Countable interface. The Countable interface defines a count() method, which returns the number of elements in the object.

For example, for a SplObjectStorage object, you can use the count() function to calculate the number of objects stored:

$storage = new SplObjectStorage();
$storage->attach(new stdClass());
$count = count($storage); // $count 为 1

Note:

• If variable is not an array, string, or object implementing the Countable interface, the count() function will return null.
• The count() function does not recursively traverse multidimensional arrays or nested objects. It only counts the number of elements in the first level.

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