How to verify if $_GET exists?

Question

How to verify if $_GET exists?

191.9k Views Asked by tckmn At 09 April 2025 at 01:02

So, I have some PHP code that looks a bit like this:

<body>
    The ID is 

    <?php
    echo $_GET["id"] . "!";
    ?>

</body>

Now, when I pass an ID like http://localhost/myphp.php?id=26 it works alright, but if there is no ID like just http://localhost/myphp.php then it outputs:

The ID is
Notice: Undefined index: id in C:\xampp\htdocs\myphp.php on line 9
!

I have searched for a way to fix this but I cannot find any way to check if a URL variable exists. I know there must be a way though.

Original Q&A

There are 7 best solutions below

Makita On 18 August 2012 at 15:15

   if (isset($_GET["id"])){
        //do stuff
    }

Julien On 18 August 2012 at 15:16

Use and empty() whit negation (for test if not empty)

if(!empty($_GET['id'])) {
    // if get id is not empty
}

Baba On 18 August 2012 at 15:16

You are use PHP isset

Example

if (isset($_GET["id"])) {
    echo $_GET["id"];
}

Asaph On 18 August 2012 at 15:17

You can use the array_key_exists() built-in function:

if (array_key_exists('id', $_GET)) {
    echo $_GET['id'];
}

or the isset() built-in function:

if (isset($_GET['id'])) {
    echo $_GET['id'];
}

Sammaye On 18 August 2012 at 15:19

Normally it is quite good to do:

echo isset($_GET['id']) ? $_GET['id'] : 'wtf';

This is so when assigning the var to other variables you can do defaults all in one breath instead of constantly using if statements to just give them a default value if they are not set.

illeas On 16 May 2016 at 09:31

Please try it:

if(isset($_GET['id']) && !empty($_GET['id'])){
   echo $_GET["id"];
 }

**Zbigniew** · Accepted Answer

You can use isset function:

if(isset($_GET['id'])) {
    // id index exists
}

You can create a handy function to return default value if index doesn't exist:

function Get($index, $defaultValue) {
    return isset($_GET[$index]) ? $_GET[$index] : $defaultValue;
}

// prints "invalid id" if $_GET['id'] is not set
echo Get('id', 'invalid id');

You can also try to validate it at the same time:

function GetInt($index, $defaultValue) {
    return isset($_GET[$index]) && ctype_digit($_GET[$index])
            ? (int)$_GET[$index] 
            : $defaultValue;
}

// prints 0 if $_GET['id'] is not set or is not numeric
echo GetInt('id', 0);

How to verify if $_GET exists?

There are 7 best solutions below

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