How to find the average value of an array avg in php

Implementation steps: 1. Use the array_sum() function to calculate the sum of all elements in the array, the syntax "$sum=array_sum($arr);"; 2. Use the count() function to calculate the length of the array, the syntax "$len=count($arr);"; 3. Use the "/" operator to divide the sum of elements by the array length to obtain the array average avg, the syntax is "$avg=$sum/$len;".

The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer

In php, you can use array_sum() and The count() function is used to find the average avg of an array.

Implementation steps:

Step 1. Use the array_sum() function to calculate the sum of all elements in the array

$sum=array_sum($arr);

Step 2: Use the count() function to calculate the length of the array (the number of elements in the array)

$len=count($arr);

Step 3: Use the "/" operator Divide the sum of elements by the length of the array to get the array average avg

$avg=$sum/$len;

Implementation example:

<?php 
header("content-type:text/html;charset=utf-8");
function f($arr){
	$sum=array_sum($arr);
	echo "数组元素和：".$sum."<br>";
	$len=count($arr);
	echo "数组长度：".$len."<br>";
	$avg=$sum/$len;
	echo "数组平均值：".$avg."<br><br>";
}


$arr=array(1,2,3,4,5,6,7,8,9,10);
var_dump($arr);
f($arr);

$arr=array(2,4,6,8,10);
var_dump($arr);
f($arr);
?>

Function description

1. array_sum() function

array_sum() function can calculate all the values ​​in the array The sum of the elements and returns the sum of the elements.

array_sum($array)

• If all elements in $array are integers, return an integer value; if one or more of the values ​​are floating point numbers, return a float Points.

• If there are elements of non-numeric type in $array, PHP will convert them into a numeric value (PHP is a weak language type and will be based on the value of the variable , automatically convert the variable to the correct data type), if the conversion fails, it will be used as a 0 value to participate in the calculation.

<?php
header("Content-type:text/html;charset=utf-8");
$array= array("10.1xy", 100, &#39;1&#39;, "0.01");
var_dump($array);
echo &#39;数组所有元素之和：&#39;. array_sum($array);
?>

#2. count() function

The method to get the length of an array in PHP is very simple, PHP provides us with two functions to calculate the length of an array, namely the count() and sizeof() functions.

The count() function can count the number of all elements in the array, or the number of attributes in the object. Its syntax format is as follows:

count($array , $mode )

The parameter description is as follows:

• $array: is the array or object to be counted;
• $mode: is an optional parameter and can be omitted.
  • If the $mode parameter is omitted, or set to COUNT_NORMAL or 0, the count() function will not detect multidimensional arrays;
  • If $mode is set to COUNT_RECURSIVE or 1, the count() function Will recursively count the number of elements in the array, especially useful for counting the number of elements in multi-dimensional arrays.

Tip: If $array is neither an array nor an object, the count() function will return 1; if $array is equal to NULL, the count() function Return 0.

Example 1: Length of one-dimensional array

<?php 
header("content-type:text/html;charset=utf-8");
$arr=array(1,2,3,4,5,6,7,8,9);
var_dump($arr);
echo "数组长度为：".count($arr);
?>

Example 2: Length of two-dimensional array

<?php
header("Content-type:text/html;charset=utf-8");
$arr= array
("张三",
25,
    array("高数","PHP教程","英语"),
);
//输出语句
var_dump($arr);
echo "数组长度为：".count($arr,1);
?>

sizeof() function is an alias of count() function, that is, the function and usage of sizeof() function are exactly the same as count() function.

Recommended learning: "PHP Video Tutorial"

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