Detailed explanation of how to use array_key_exists() function example in PHP

array_key_exists() Definition and usage

array_key_exists() Function Determine whether a certain array exists The specified key, if the key exists, returns true, otherwise returns false.

Syntax
array_key_exists(key,array)
Parameter Description
key required. Specifies the key name.
array required. Specifies the input array.

Example 1

<?php 
$a=array("a"=>"Dog","b"=>"Cat"); 
if (array_key_exists("a",$a)) 
{ 
echo
 "Key exists!"; 
} 
else
 
{ 
echo "Key does not exist!"; 
} 
?>

Output:

Key exists!
Example 2

<?php 
$a=array("a"=>"Dog","b"=>"Cat"); 
if (array_key_exists("c",$a)) 
{ 
echo "Key exists!"; 
} 
else 
{ 
echo "Key does not exist!"; 
} 
?>

Output:

Key does not exist!
Example 2

<?php 
$a=array("Dog",Cat"); 
if (array_key_exists(0,$a)) 
{ 
echo "Key exists!"; 
} 
else 
{ 
echo "Key does not exist!"; 
} 
?>

Output:

Key exists!

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