Php array function sequence: array_key_exists ()-query whether the array key name exists _ PHP Tutorial

Array_key_exists () of the php array function sequence-query whether the array key name exists. Array_key_exists () definition and usage the array_key_exists () function determines whether a specified key exists in an array. if the key exists, true is returned; otherwise, false is returned. Syntax ar Array_key_exists () definition and usage
The array_key_exists () function checks whether a specified key exists in an array. if the key exists, true is returned; otherwise, false is returned.

Syntax
Array_key_exists (key, array)
Parameter description
Key is required. Specifies the key name.
Array is required. Specifies the input array.

Example 1

The code is as follows:

$ A = array ("a" => "Dog", "B" => "Cat ");
If (array_key_exists ("a", $ ))
{
Echo "Key exists! ";
}
Else
{
Echo "Key does not exist! ";
}
?>

Output:

Key exists!
Example 2

The code is as follows:

$ A = array ("a" => "Dog", "B" => "Cat ");
If (array_key_exists ("c", $ ))
{
Echo "Key exists! ";
}
Else
{
Echo "Key does not exist! ";
}
?>

Output:

Key does not exist!
Example 2

The code is as follows:

$ A = array ("Dog", Cat ");
If (array_key_exists (0, $ ))
{
Echo "Key exists! ";
}
Else
{
Echo "Key does not exist! ";
}
?>

Output:

Key exists!

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