php check if array subscript exists

PHP method to check whether array subscript exists

array_key_exists() function

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.

Instance:

<?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!

Instance:

<?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!

Instance:

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

Output:

Key exists!

Recommended tutorial: PHP video tutorial

The above is the detailed content of php check if array subscript exists. For more information, please follow other related articles on the PHP Chinese website!