How to sum arrays in php

In PHP, summing through arrays is a common operation. Array summation is the operation of adding the values ​​of all elements in an array to obtain a sum. This operation is very simple and easy to implement in PHP. In this article, we will introduce how to sum arrays in PHP.

Basic Array Sum

We can use array_sum(), a built-in function in PHP, to calculate the sum of all elements in an array. This function accepts an array as argument and returns the sum of all elements in the array. The following is an example of how to use this function:

$numbers = [1, 2, 3, 4, 5];

$sum = array_sum($numbers);

echo $sum; // 输出 15

The above code first defines an array containing 5 values, then uses the array_sum() function to calculate the sum of all elements of this array, and stores the result in in the variable $sum. Finally, use the echo statement to print out the sum of this array.

Multi-dimensional array summation

In PHP, we can also perform sum operations on multi-dimensional arrays. When summing multidimensional arrays, we need to sum each subarray first and then add their sums. The following is an example code that uses a recursive algorithm to calculate the sum of multi-dimensional arrays:

$array = [
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9]
];

function sum_array($array) {
  $sum = 0;

  foreach ($array as $value) {
    if (is_array($value)) {
      $sum += sum_array($value);
    } else {
      $sum += $value;
    }
  }

  return $sum;
}

$total_sum = sum_array($array);

echo $total_sum; // 输出 45

The above code first defines a variable $array that contains a multi-dimensional array, and defines a recursive function named sum_array() . This function accepts an array as a parameter and returns the sum of all elements in the array. In the function, a variable $sum is first defined to store the sum of all elements in the array. Next, loop through each element in the array. If the current element is an array, then it is summed recursively. Otherwise, the value of this element is added directly to the $sum variable. Finally, the function returns the total and stores it in the variable $total_sum, and finally outputs the total.

Summary

PHP array summation is a very common and useful operation. By using PHP built-in function array_sum(), we can easily calculate the sum of all elements in an array. When we need to sum multi-dimensional arrays, we can use recursive algorithms to achieve it. I hope this article can help you master PHP array sum.

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