How to use array_key_exists and isset in php

This article mainly introduces the method of PHP to determine whether there is a specified key (key) in the array. It analyzes the usage skills of array_key_exists and isset in PHP with examples. It is of great practical value. Friends who need it can refer to it

The example of this article describes how PHP determines whether the specified key exists in the array. The specific analysis is as follows:

There are two functions in php to determine whether the array contains the specified key, namely array_key_exists and isset

array_key_exists syntax is as follows

array_key_exists($key, $array)

If the key The isset function syntax is as follows:

isset($array[$key])

If the key exists, it returns true

The demo code is as follows:

<?php
$array = array("Zero"=>"PHP", "One"=>"Perl", "Two"=>"Java");
print("Is &#39;One&#39; defined? ".array_key_exists("One", $array)."\n");
print("Is &#39;1&#39; defined? ".array_key_exists("1", $array)."\n");
print("Is &#39;Two&#39; defined? ".isset($array["Two"])."\n");
print("Is &#39;2&#39; defined? ".isset($array[2])."\n");
?>

The return result is as follows:

Is 'One' defined? 1
Is '1′ defined?
Is 'Two' defined? 1
Is '2′ defined?

Summary: The above is the entire content of this article, I hope it will be helpful to everyone's study.

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