Getting Error when Wrong $_GET Parameter in URL is Used

Question

and can't get this to work. I want to get variable from URL, like:

domain.com?region=STATE

if (empty($_GET)) {
    echo 'American';

}

else {
    $t = $_GET["region"];
    if ($t == "Texas") {
        echo "Texan";
    } elseif ($t == "California") {
        echo "Californian";
    } else {
        echo "American";
    }
}

This does work. However in case there's wrong parameter input, like:

domain.com?asdasd=whatever

I get an error:

"Notice: Undefined index: region in test.php on line 19"

Can you tell me how can I prevent this error from appearing and basically treat it as empty variable and return "American" instead?

I tried this code, but it doesn't work:

if (empty($_GET)) {
    echo 'American';

}
elseif ($_GET != "region") {
    echo 'Anything Else';
}
else {
    $t = $_GET["region"];
    if ($t == "Texas") {
        echo "Texan";
    } elseif ($t == "California") {
        echo "Californian";
    } else {
        echo "American";
    }
}

Even if URL is true:

domain.com?region=Texas

is still get "Anything Else" in the output.

Possible duplicate of PHP: "Notice: Undefined variable", "Notice: Undefined index", and "Notice: Undefined offset" — Qirel
– Qirel, Commented May 20, 2017 at 7:21

Enstage · Accepted Answer · 2017-05-20 07:18:19Z

1

Use isset(($_GET['region']) as it does not emit a notice if fed an undefined variable:

if (!isset($_GET['region'])) {
    echo 'American';
} else {
    $t = $_GET["region"];
    if ($t == "Texas") {
        echo "Texan";
    } elseif ($t == "California") {
        echo "Californian";
    } else {
        echo "American";
    }
}

answered May 20, 2017 at 7:18

Enstage

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1 Comment

Enstage Over a year ago

If mine is the correct answer then check the green tick below the voting buttons to mark it as such :)

Amit Gaud · Accepted Answer · 2017-05-20 07:19:16Z

1

USE $_GET['region'] not $_GET itself

 if (!isset($_GET["region"]) || empty($_GET["region"])) {
        echo 'American';

    }
    else {
        $t = $_GET["region"];
        if ($t == "Texas") {
            echo "Texan";
        } elseif ($t == "California") {
            echo "Californian";
        } else {
            echo "American";
        }
    }

edited May 20, 2017 at 7:19

answered May 20, 2017 at 7:14

Amit Gaud

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2 Comments

reizer Over a year ago

thanx Amit, but it still doesn't work. I get the same output "Anything Else" if I use one of the defined states. IE: test.php?region=Texas

Amit Gaud Over a year ago

@reizer try this I have changed litile logic in code

Professor Abronsius · Accepted Answer · 2017-05-20 07:19:49Z

1

You could use array_key_exists('region',$_GET) to test if the parameter exists like this perhaps

if( !empty( $_GET ) ){

    $t = array_key_exists( 'region', $_GET ) && !empty( $_GET['region'] ) ? strtolower( $_GET['region'] ) : false;

    if( $t ){
        switch( $t ){
            case 'texas': echo 'Texan';break;
            case 'california': echo "Californian"; break;
            default: echo 'Other State'; break;
        }
    } else {
        echo 'Anything Else';
    }
} else {
    echo 'American';
}

answered May 20, 2017 at 7:19

Professor Abronsius

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1 Comment

reizer Over a year ago

wow thanx, you even included lowercase/Uppercase correction just in case.

Kumar Abhirup · Accepted Answer · 2017-05-20 07:22:40Z

1

Try this too:

<?php

        if (empty($_GET)) {
            echo 'American';
        } else if($_GET){
            echo 'No Error! (Anything Else)';
        }

        else {
            $t = $_GET["region"];
            if ($t == "Texas") {
                echo "Texan";
            } elseif ($t == "California") {
                echo "Californian";
            } else {
                echo "American";
            }
        }

    ?>

answered May 20, 2017 at 7:22

Kumar Abhirup

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