PHP is a server-side scripting language commonly used for web development. Among them, array is a common data type used to store a set of related values. This article will introduce how to use PHP to define an array and find its average.

Define array

In PHP, you can define an array in the following way:

1. Indexed array

Indexed array is the simplest Array form, where each element has a unique subscript. The subscripts start from 0, and the last subscript is the length of the array minus 1.

$numbers?=?array(1,?2,?3,?4,?5);

You can also define an index array in the following way:

$numbers[0]?=?1;
$numbers[1]?=?2;
$numbers[2]?=?3;
$numbers[3]?=?4;
$numbers[4]?=?5;

2. Associative array

Associative array is another common array form, in which each Each element has a unique key name, which can be an integer or a string. The key name and element value are connected with the "=>" symbol.

$student?=?array("name"=>"Tom",?"age"=>20,?"gender"=>"male");

You can also define associative arrays in the following way:

$student?=?array();
$student["name"]?=?"Tom";
$student["age"]?=?20;
$student["gender"]?=?"male";

Find the average

Finding the average of an array requires the following steps:

1. Find the sum of array elements.
2. Calculate the average, which is the sum divided by the array length.

The following is a sample code for calculating the average of an array:

$numbers?=?array(1,?2,?3,?4,?5);

//?求元素總和
$sum?=?0;
for?($i?=?0;?$i?<?count($numbers);?$i++)?{
??$sum?+=?$numbers[$i];
}

//?計算平均數(shù)
$avg?=?$sum?/?count($numbers);

echo?"數(shù)組平均數(shù)為：".$avg;

Run the above code, the output is as follows:

數(shù)組平均數(shù)為：3

In addition, if there are numbers in the array that are not numbers Element, you can use the is_numeric() function to determine and skip calculation. For example:

$numbers?=?array(1,?2,?"3",?4,?5);
$sum?=?0;
$count?=?0;
for?($i?=?0;?$i?<?count($numbers);?$i++)?{
??if?(is_numeric($numbers[$i]))?{
????$sum?+=?$numbers[$i];
????$count++;
??}
}

$avg?=?$sum?/?$count;
echo?"數(shù)組平均數(shù)為：".$avg;

The above code will skip the non-numeric element "3", and the output will still be 3.

Summary

Arrays in PHP are an important data type, often used to store a set of related values. Using arrays can also simplify code logic and improve development efficiency. This article introduces how to use PHP to define an array and find its average. I hope it will be helpful to beginners.

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