How to count the number of array elements in php

In PHP, array is a very commonly used data type. When we need to count the number of times a certain element appears in an array, we can use PHP's built-in function to count. This article will introduce how to count the number of elements in an array, the number of different elements and the number of occurrences in PHP.

1. Count the number of array elements

In PHP, you can use the PHP built-in function count() to count the number of array elements. This function can return the number of elements in the array.

Sample code:

$fruits = array("apple", "orange", "banana", "pear");
echo count($fruits); //输出4

In the above code, we define an array $fruits containing 4 elements, and use the count() function to count the number of elements in the array. The output is 4.

2. Count the number of different elements in an array

In PHP, you can use the PHP built-in function array_count_values() to count the number of different elements in an array. This function can return a new array. In the new array, the keys are different elements that appear in the original array, and the value is the number of times the element appears.

Sample code:

$fruits = array("apple", "orange", "banana", "pear", "apple", "apple");
$count_fruits = array_count_values($fruits);
print_r($count_fruits);

In the above code, we define an array $fruits containing 6 elements, and use the array_count_values() function to count the number of different elements in the array. The output result is:

Array (
    [apple] => 3
    [orange] => 1
    [banana] => 1
    [pear] => 1
)

The above results indicate that in the original array $fruits, the "apple" element appears three times, and the "orange", "banana" and "pear" elements each appear only once.

3. Count the number of times a certain element appears in an array

In PHP, to count the number of times a certain element appears in an array, you can use the PHP built-in function array_count_values() combined with the array index.

Sample code:

$fruits = array("apple", "orange", "banana", "pear", "apple", "apple");
$count_apple = 0;
foreach ($fruits as $fruit) {
    if ($fruit == "apple") {
        $count_apple++;
    }
}
echo $count_apple; //输出3

In the above code, we defined an array $fruits containing 6 elements, and used a foreach loop to traverse the array and count the occurrences of the "apple" element. frequency. The output is 3.

In addition to the above methods of using the array_count_values() function and foreach loop, we can also use the PHP built-in function array_filter() combined with anonymous functions.

Sample code:

$fruits = array("apple", "orange", "banana", "pear", "apple", "apple");
$count_apple = count(array_filter($fruits, function($fruit) {
    return $fruit == "apple";
}));
echo $count_apple; //输出3

In the above code, we use the array_filter() function to filter the elements in the array $fruits, retaining only elements with the value "apple". Then use the count() function to count the number of elements in the array, which is the number of times the "apple" element appears in the original array.

To sum up, in PHP, you can use the count() function, array_count_values() function, foreach loop and array_filter() function combined with anonymous functions to count arrays. In actual development, selection based on specific demand scenarios can more efficiently count elements in the array.

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