How to sum recursive array values ​​in php

When developing PHP applications, sometimes you need to perform recursive operations on multi-dimensional arrays, such as summing all the values ​​in the array, which requires the use of recursive functions. In this article, we will share how to sum all the values ​​in an array using PHP recursive function.

1. What is a recursive function?

A recursive function refers to a function that calls the function itself within a function. It is a very different programming technique. Recursive functions are very useful when solving some repetitive problems, such as processing data in multi-dimensional arrays.

2. What is a multidimensional array?

A multidimensional array is an array that contains other arrays. Multidimensional arrays can be of arbitrary depth, and each element can be an array or other type of data.

For example, the following is a multidimensional array containing 3 arrays:

$arr = array(
  array(1, 2, 3),
  array(4, 5, 6),
  array(7, 8, 9)
);

3. How to perform recursive summation of multidimensional arrays?

For operations on multi-dimensional arrays, we need to use recursive functions. The following is a recursive function that can be used to sum all the values ​​in a multi-dimensional array:

function recursive_array_sum($array) {
  $sum = 0;
  foreach ($array as $val) {
    if (is_array($val)) {
      $sum += recursive_array_sum($val);
    } else {
      $sum += $val;
    }
  }
  return $sum;
}

This function uses a foreach loop to iterate through each element in the array. If the element is of array type, the recursive function is called, otherwise the value of the element is added to the $sum variable. Finally, the function returns the value of the $sum variable, which is the sum of all values ​​in the multidimensional array.

4. How to use recursive functions to sum?

The following is an example that demonstrates how to use a recursive function to sum all values ​​in a multidimensional array:

$arr = array(
  array(1, 2, 3),
  array(4, 5, 6),
  array(7, 8, 9)
);
$sum = recursive_array_sum($arr);
echo $sum; //输出45

In this example, we first declare a multidimensional array $arr and then call the recursion The function recursive_array_sum() sums all the values ​​in the array. Finally, we output the summation result 45 to the screen.

5. Summary

Recursive function is a very useful programming technique. It can be used to perform recursive operations on multi-dimensional arrays, such as summing all the values ​​in the array. In this article, we introduce a recursive function that can be used to sum all the values ​​in a multidimensional array. If you need to do more operations with multi-dimensional arrays, learn more about the use of PHP recursive functions.

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