PHP array function sequence array_key_exists() - Find whether the array key exists_PHP tutorial

array_key_exists() Definition and usage
array_key_exists() function determines whether the specified key exists in an array. If the key exists, it returns true, otherwise it returns false.

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

Example 1

Copy code The code is as follows:

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

Output:

Key exists!
Example 2

Copy code The code is as follows:

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

Output:

Key does not exist!
Example 2

Copy code The code is as follows:

< ?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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