How to determine how many identical values ​​there are in an array in PHP

PHP method to determine whether there are several identical values ​​in an array: 1. Using loops and counters, you can use a loop to traverse each element of the array, and then use a counter to record the number of times the same value has been reached; 2. Use the array_count_values() function to count the number of occurrences of each value in the array and return an associative array, where the key is the value of the original array and the value is the number of occurrences of the corresponding value; 3. Use the array_filter() function Methods etc.

The operating environment of this tutorial: windows10 system, php8.1.3 version, DELL G3 computer.

PHP is a widely used scripting language, especially suitable for web development. In PHP, array is an important data structure used to store and manage multiple values. Sometimes, we need to determine how many identical values ​​there are in an array in order to further process the array. This article will introduce several different methods to determine how many identical values ​​there are in a PHP array.

1. Method of using loops and counters

You can use a loop to traverse each element of the array, and then use a counter to record the number of times the same value is used. The specific implementation code is as follows:

function countDuplicates($array, $value) {
$count = 0;
foreach($array as $element) {
if($element == $value) {
$count++;
}
}
return $count;
}

Then you can call this function to get the number of occurrences of a certain value in the array, for example:

$array = [1, 2, 3, 4, 2, 2];
$count = countDuplicates($array, 2);
echo "值为2的元素出现了" . $count . "次";

This method is relatively simple, but the performance is poor. For large Arrays may affect efficiency.

2. Method of using array_count_values() function

PHP provides a built-in function array_count_values(), which can count the number of occurrences of each value in the array, and Returns an associative array, where the key is the value of the original array and the value is the number of occurrences of the corresponding value. The specific sample code is as follows:

$array = [1, 2, 3, 4, 2, 2];
$countArray = array_count_values($array);
$count = $countArray[2];
echo "值为2的元素出现了" . $count . "次";

Compared with the first method, this method has more concise code, but counting the entire array may take up more memory.

3. How to use the array_filter() function

The array_filter() function can filter array elements according to specified conditions and return array elements that meet the conditions. We can use this function to filter out all elements whose value is equal to the target value, and then count the number of elements that meet the condition. The specific implementation code is as follows:

$array = [1, 2, 3, 4, 2, 2];
$count = count(array_filter($array, function($element) {
return $element == 2;
}));
echo "值为2的元素出现了" . $count . "次";

Compared with the second method, this method is more concise and saves memory usage.

No matter which method is used, you can easily determine how many identical values ​​there are in the PHP array and choose the method that suits your needs. When dealing with large arrays, performance and memory usage can be considered to choose an appropriate method. Hope this article is helpful to you!

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