How to get the index of the maximum value in an associative array in PHP

This article mainly introduces to youHow to get the index of the maximum value in an associative array .

#During the interview process for PHP job seekers, PHP arrays can be said to be a very common test point. For example, what are the classifications of PHP arrays? How to find the maximum and minimum values? What is an index? Basic and important issues such as these all require everyone to master and study. The focus of this section is to explain to you how to obtain the index of the largest item in an associative array.

Recommended reference study: "PHP Tutorial"

First of all, you need to briefly understand the basic knowledge related to arrays.

An array in PHP is actually an ordered map. A mapping is a type that associates values ​​to keys. In other words, arrays are special variables that can hold more than one value at the same time.

There are three types of arrays in PHP: Index array (array with numeric index), Associative array (array with specified keys), Multidimensional array (array containing one or more arrays).

Below we will introduce to you through a simple example the implementation method of getting the index of the maximum value in an associative array.

The code example is as follows:

<?php
$x = array(
&#39;value1&#39; => 3021,
&#39;value2&#39; => 2365,
&#39;value3&#39; => 5215,
&#39;value4&#39; => 5214,
&#39;value5&#39; => 2145);
reset($x);   
arsort($x);
$key_of_max = key($x);
echo "最大值的索引: ".$key_of_max."\n";

The result is as follows:

##In the above code, we can directly see that in the associative array The maximum value is 5215, and the output result is also the index of the maximum value.

The method implemented here mainly involves several important functions:

reset(): Point the internal pointer of the array to the first unit.

arsort(): Sort the array in reverse and maintain the index relationship.

key(): Returns the key name of the element currently pointed to by the internal pointer of the array.

This article is an introduction to the method of obtaining the index of the maximum value in an associative array in PHP. It is very simple and easy to understand. I hope it will be helpful to friends in need!

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