PHP empty() error message

Question

I have just started learning and have put together the form below. The confusion I have is when I use empty to validate if the user selected or entered any information, the code generates the error below.

I noticed if I have the following lines of code

if(empty($gender)) {
        $errormessage[2] = "Please select your gender";
    }

as

if(empty($_POST["gender"])) {
        $errormessage[2] = "Please select your gender";
    }

and

if(empty($gender)) {
        $errormessage[2] = "Please select your gender";
    }

as

if(empty($_POST["gender"])) {
        $errormessage[2] = "Please select your gender";
    }

I do not see the error message. I take it that error message is being generated because of the lines of code $_POST for the gender and media form elements which are radio buttons and checkboxes respectively. However if I want to initialize all the variables at the top, what is the best way to do so?

/* <?php

if(isset($_POST["submit"])) {

    $fname = $_POST["fname"];
    $lname = $_POST["lname"];
    $gender = $_POST["gender"];
    $age = $_POST["age"];
    $address = $_POST["address"];
    $media = $_POST['media'];

    $errormessage =  array();

    if(empty($fname)) {
        $errormessage[0] = "Please enter your first name";
    }

    if(empty($lname)) {
        $errormessage[1] = "Please enter your last name";
    }

    if(empty($gender)) {
        $errormessage[2] = "Please select your gender";
    }

    if(empty($age)) {
        $errormessage[3] = "Please select your age";
    }

    if(empty($address)) {
        $errormessage[4] = "Please enter your address";
    }

    if(empty($media)) {
        $errormessage = "Please select the type of media";

    }

}
?>
<html>
<head>
    <title>Sample Registration</title>
</head>
<body>
    <h2>Sample registration</h4>
        <form name="registration" method="post" action="registration.php">
            <div>
                First Name: <br />
                <input type="text" name="fname" value="">
            </div>

            <div>
                Last Name: <br />
                <input type="text" name="lname" value="">
            </div>

            <div>
                Gender: <br />
                male<input type="radio" name="gender" value="male">
                female<input type="radio" name="gender" value="female">
            </div>

            <div>
                Age: <br />
                <select name="age">
                    <option value="">Please select your age</option>
                    <option value="18-25">18-25</option>
                    <option value="26-33">26-33</option>
                </select>
            </div>

            <div>
                Address: <br />
                <textarea name="address" cols="10" rows="10"></textarea>
            </div>

            <div>
                Sign-me up: <br />
                <input type="checkbox" name="media['newsletter']" value="newsletter"> newsletter
                <input type="checkbox" name="media['specials']" value="specials"> specials
                <input type="checkbox" name="media['events']" value="events"> events

            <div>
                <input type="submit" name="submit" value="submit">
            </div>
        </form>
</body>
</html>

*/

/* Error Message */

! ) Notice: Undefined index: gender in C:\Program Files\EasyPHP-5.3.5.0\www\registration.php on line 7
Call Stack
#   Time    Memory  Function    Location
1   0.0004  341792  {main}( )   ..\registration.php:0
Dump $_SERVER

$_SERVER['REMOTE_ADDR'] =



string '127.0.0.1' (length=9)

$_SERVER['REQUEST_METHOD'] =



string 'POST' (length=4)

$_SERVER['REQUEST_URI'] =



string '/registration.php' (length=17)

Variables in local scope (#1)

$address =

    Undefined

$age =

    Undefined

$errormessage =

    Undefined

$errormsg =

    Undefined

$fname =



string '' (length=0)

$gender =

    Undefined

$lname =



string '' (length=0)

$media =

    Undefined

( ! ) Notice: Undefined index: media in C:\Program Files\EasyPHP-5.3.5.0\www\registration.php on line 10
Call Stack
#   Time    Memory  Function    Location
1   0.0004  341792  {main}( )   ..\registration.php:0
Variables in local scope (#1)

$address =



string '' (length=0)

$age =



string '' (length=0)

$errormessage =

    Undefined

$errormsg =

    Undefined

$fname =



string '' (length=0)

$gender =



null

$lname =



string '' (length=0)

$media =

    Undefined

where are you expecting the error message to show? I don't see where you are trying to display the message. — MacAnthony
– MacAnthony, Commented Apr 14, 2011 at 2:38

Ryan · Accepted Answer · 2011-04-14 05:10:04Z

4

You'll want to check whether those $_POST['gender'] and $_POST['media'] variables were actually set in the HTTP POST request before you go accessing them; a better solution to initialize each $_POST var might be something like this:

$fname = isset( $_POST['fname'] ) ? $_POST['fname'] : '';

The above ternary assignment is equivalent to running the following logical expression for every single $_POST variable in which you're interested:

if( isset( $_POST['fname'] ) ) {
    $fname = $_POST['fname'];
} else {
    $fname = '';
}

If you implement either of these, you won't get a notice if you run empty() on $gender; furthermore, if $_POST['gender'] wasn't set, empty() will still behave the way you expect. It adds a little verbosity, but to rewrite your example you might try:

if( isset( $_POST["submit"] ) ) {

    $fname = isset( $_POST['fname'] ) ? $_POST["fname"] : '';
    $lname = isset( $_POST['lname'] ) ? $_POST["lname"] : '';
    $gender = isset( $_POST['gender'] ) ? $_POST["gender"] : '';
    $age = isset( $_POST['age'] ) ? $_POST["age"] : '';
    $address = isset( $_POST['address'] ) ? $_POST["address"] : '';
    $media = isset( $_POST['media'] ) ? $_POST['media'] : '';

    $errormessage =  array();
    if( empty( $fname ) )
        $errormessage[] = "Please enter your first name";
    if( empty( $lname ) )
        $errormessage[] = "Please enter your last name";
    if( empty( $gender ) )
        $errormessage[] = "Please select your gender";
    if( empty( $age ) )
        $errormessage[] = "Please select your age";
    if( empty( $address ) )
        $errormessage[] = "Please enter your address";
    if( empty( $media ) )
        $errormessage[] = "Please select the type of media";
}

Of course, you'd want to clean your data if you're going to use it in a SQL context, but that should at least get you around the error you're facing.

If you had a lot of these variables--or were repeating this task often--you might consider rolling it up into a function!

edited Apr 14, 2011 at 5:10

answered Apr 14, 2011 at 2:37

Ryan

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16 Comments

PeanutsMonkey Over a year ago

Thanks Ryan. Considering I am new to the world of PHP, I am yet to learn about functions especially custom functions. Furthermore, I don't quite follow your example as I have no idea what ? does as well as : ''; in the code example of $fname = isset( $_POST['fname'] ) ? $_POST["fname"] : '';. Would you mind elaborating what it is and does and when I would use it?

Ryan Over a year ago

Sure! the ?: you see there is the ternary operator in PHP and it works like this: (condition ? "true!" : "false!") for the entire expression enclosed in parentheses, if condition evaluates to true, then the whole expression evaluates to "true!"; otherwise, the whole expression evaluates to "false!"--it's really just a shortcut for if(){}else{} if you want to think of it that way

PeanutsMonkey Over a year ago

Sorry. I still don't follow. What is the condition in the code above? What are we testing as true or false?

Ryan Over a year ago

In this code: $b = true; $val = ( $b ? "yes" : "no" );, $val == "yes", but in this code: $b = false; $val = ( $b ? "yes" : "no" );, $val == "no". Does that make more sense?

PeanutsMonkey Over a year ago

Yes it does at a very high level. Let me break it down and correct me if I am wrong. I'll use the code I was working on. $fname = ($_POST["gender"] = true ? "yes" : "no"); $fname == "yes". Is that correct? I don't still follow how this is similar with the example you gave. Sorry if I am not following as quickly.

|

jrn.ak · Accepted Answer · 2011-04-14 02:37:46Z

2

Try using !isset() instead of empty().

As a side-note, the way you're assigning your variables will create warning notices if that $_POST value doesn't exist. If you'd like to remove those notices, use @Ryan's solution.

answered Apr 14, 2011 at 2:37

jrn.ak

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4 Comments

PeanutsMonkey Over a year ago

Why would I use !isset when my understanding is that all I am saying that if isset is not true, then return error message. I know that the elements are not set and returning a NULL value (I think), hence I am using empty() unless I have misunderstood the use of isset.

jrn.ak Over a year ago

Example: if $_POST['blah'] doesn't exist in $_POST, then $var = $_POST['blah'] will fail and $var will not be set to anything.

PeanutsMonkey Over a year ago

Ok, if it not set to anything them empty should be able to capture the failure. Is that not right?

jrn.ak Over a year ago

Technically yes, but you're still generating warning notices. They're not fatal, but they add to your error log and can result in unpredictable behavior in your script.

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