How to use a custom function to find the average of an array in PHP

PHP is a popular programming language that is widely used in web development. Arrays are one of the important data types in PHP and are often used to store and manipulate data. Calculating the average of an array is a basic task in PHP programming. It can be achieved using the built-in functions provided by PHP or writing a custom function. This article will show you how to write a custom function to find the average of an array.

1. Built-in function to calculate the average value

In PHP, you can use the built-in functions array_sum() and count() to calculate the value of an array The sum and the number of elements are then divided to get the average. Here is a sample code:

$array = array(2,4,6,8,10);
$sum = array_sum($array);
$count = count($array);
$average = $sum / $count;
echo $average;

The above code will output an average of 6.

While it is easy to find the average of an array using the built-in function, it does not work in all cases. For example, if the array contains elements of a non-numeric type, or if the array is empty, the built-in function returns an error. In this case, a custom function may be more suitable.

2. Custom function to find the average value

The following is a custom function to find the average value:

function array_average($array){
    $sum = 0;
    $count = 0;
    foreach($array as $value){
        if(is_numeric($value)){
            $sum += $value;
            $count++;
        }
    }
    return ($count > 0) ? ($sum / $count) : NULL;
}

This function will traverse all the elements in the array, if A numeric type that is added to the sum and incremented by the number of elements. Finally return the average value. Note that the is_numeric() function is used in the function to determine whether the element is of numeric type to avoid non-numeric type elements from affecting the calculation results. If the array is empty or contains no numeric elements, the function returns NULL.

In order to test this function, we can use the following code:

$array1 = array(2,4,6,8,10);
$array2 = array(1,'a',3,'b',5);
$array3 = array();

echo array_average($array1) . "<br/>";
echo array_average($array2) . "<br/>";
echo array_average($array3) . "<br/>";

The output result is as follows:

6
3

As you can see, the function successfully calculated the average of the first array , and correctly handles non-numeric elements in the second array and the third empty array.

3. Conclusion

Although PHP provides many built-in functions to handle arrays, writing custom functions is also very useful. Custom functions can be optimized for specific needs and provide more accurate results and better error handling. In this article, we demonstrate how to use a custom function to calculate the average of an array and compare it to using a built-in function. The author believes that developers should flexibly use built-in functions and custom functions to obtain better experience and efficiency in PHP programming.

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