PHP finds the value of array arr sum

In PHP, processing arrays is a very common operation. Sometimes, we need to find the sum of all elements in an array. PHP provides many methods to accomplish this task.

1. Use a loop to traverse an array and calculate the sum

One of the simplest ways to calculate the sum of an array is to use a loop to traverse the array and sum each element. The implementation code is as follows:

$sum = 0; // 初始化数组总和为0
$arr = array(1, 2, 3, 4, 5); // 要求和的数组

foreach ($arr as $value) { // 循环遍历数组
    $sum += $value; // 将数组元素加入总和中
}

echo "数组总和为：".$sum; // 输出数组总和

This code loops through all elements in the array using foreach and uses the $sum variable to calculate the array sum. The final result is as follows:

数组总和为：15

This method, although simple and easy to implement, may cause performance issues when dealing with large arrays because it requires traversing the entire array.

2.array_sum() function

PHP provides a function called array_sum(), which can be used to calculate the sum of all elements in an array. is another simple way to calculate the sum of an array. The implementation code is as follows:

$arr = array(1, 2, 3, 4, 5); // 要求和的数组
$sum = array_sum($arr); // 使用array_sum()函数计算数组总和

echo "数组总和为：".$sum; // 输出数组总和

This code passes the array to be summed as a parameter to the array_sum() function, and stores the returned sum in the $sum variable . The end result is the same as the previous method:

数组总和为：15

This method is much faster than the previous method because its implementation does not require the use of a loop to traverse the entire array.

3. Use the array_reduce() function

Another way is to use the array_reduce() function. This function is a high-order function that can The element performs the specified operation. The implementation code is as follows:

$arr = array(1, 2, 3, 4, 5); // 要求和的数组
$sum = array_reduce($arr, function($carry, $item) { // 使用array_reduce()函数进行求和
    $carry += $item; // 将元素加入到总和中
    return $carry; // 返回更新后的总和
});

echo "数组总和为：".$sum; // 输出数组总和

This code sums the arrays by using the array_reduce() function, and uses an anonymous function to specify the calculation method. First initialize the $carry parameter (that is, the initial value) to 0, and pass the elements in the array as the $item parameter each time the anonymous function is called, and add it to $carry variable. In this case, the anonymous function just needs to return the updated sum.

Summary

The above are three commonly used methods for calculating the sum of arrays. Among them, the simplest method is to use a loop to loop through the array and calculate their sum. The other two methods are to use the array_sum() function and the array_reduce() function, which are PHP predefined functions that can easily accomplish this task.

For processing large arrays, the array_sum() function and the array_reduce() function may be more efficient. However, for small and medium-sized arrays, looping over the array will also get the job done, and the code will be easier to read and understand.

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