Undefined index PHP with echo radio buttons value

Question

<h1> Hotel kamer reservering </h1>
<br><br>

<form method="POST">
<input name="radio" type="radio" value="éénpersoonskamer">éénpersoonskamer</input><br><br>
<input name="radio1" type="radio" value="tweepersoonskamer">tweepersoonskamer</input><br><br>
<input name="radio2" type="radio" value="ontbijt">ontbijt</input><br><br><br>
<input name="radio3" type="radio" value="lunch">lunch</input><br><br><br>
<input name="radio4" type="radio" value="diner">diner</input><br><br><br>
<input name="submit" type="submit" <value="Klik"></input>
</form>

<?php 

if(isset($_POST['submit']) and ! empty($_POST['submit'])) {
    if(isset($_POST['radio']) ||  ($_POST['radio1']) || ($_POST['radio2']) || ($_POST['radio3']) || ($_POST['radio4']) ) {
        $radio = $_POST['radio'] . '&nbsp' . $_POST['radio1'] . '&nbsp' . $_POST['radio2'] . '&nbsp' . $_POST['radio3'] . '&nbsp' . $_POST['radio4'];
        echo $radio;
    }
}
?>

I am a beginner with PHP, am learning it now but i can't seem to lose the undefined index message. If i choose all then it won't give a bad message. Can someone explain me how i can fix this with this code and how i can resolve it with another code in the future.

I am thankfull for your time.

All of those radio buttons have to have the same name. That's how they are grouped together. — John Conde, May 03 '18 at 20:45
`You don't need to use `isset()` and `!empty()` for the same variable. `empty()` does its own `isset()` check. — Barmar, May 03 '18 at 20:50
You should share what errors you are seeing in the question via an [edit]. — , May 03 '18 at 20:52
You need to specifiy that it's for the submit button @Barmar They'll probably think that you're talking about the other `isset()`'s. — Funk Forty Niner, May 03 '18 at 20:52
Your HTML is very wrong. `` elements are not containers, they don't have `` tags. — Barmar, May 03 '18 at 20:52
@FunkFortyNiner That's the only one where he uses both `isset()` and `!empty()`. — Barmar, May 03 '18 at 20:53
I used different names because i want to be able to click more radio options — , May 04 '18 at 06:51
@user9737826 Radio buttons are normally put into groups, where you select one choice from each group. Otherwise you should be using checkboxes, not radio buttons. All the choices in a group have the same name. — Barmar, May 04 '18 at 19:35

score 1 · Answer 1 · answered May 03 '18 at 20:57

1

You're only calling isset() on the $_POST variable for the first radio button. You need to check that all the radio buttons are set. If any of them aren't set, you'll get that warning.

if(isset($_POST['radio'], $_POST['radio1'], $_POST['radio2'], $_POST['radio3'], $_POST['radio4']) ) {
    $radio = $_POST['radio'] . '&nbsp' . $_POST['radio1'] . '&nbsp' . $_POST['radio2'] . '&nbsp' . $_POST['radio3'] . '&nbsp' . $_POST['radio4'];
    echo $radio;
}

answered May 03 '18 at 20:57

Barmar

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What is the difference? – May 04 '18 at 07:10
Did you select something from every radio group? It only echoes something when there's a value for *all* the `$_POST['radioX']` parameters. – Barmar May 04 '18 at 19:34

score 0 · Answer 2 · answered May 03 '18 at 21:12

0

1) Remove typo "<" before "value" in <input name="submit" type="submit" <value="Klik"></input> 2) This is pointless: "empty($_POST['submit']" 3) All radio buttons should have the same name, not "radio1", "radio2" etc., perhaps it would be better to use checkboxes here if you want to be able to select/deselect more than one option 4) The only reason you're getting an error is because you're checking "radio" variable if it exists with isset($_POST['radio']) as for other radio inputs you're only checking if they have any kind of value: ($_POST['radio1']), you should be checking if all of them exist before checking their values :)

answered May 03 '18 at 21:12

MrTaikoDrummer

1

I don’t understand the last part, how can i fix that? – May 04 '18 at 07:08
You need to change every `($_POST['radio1'])` to `isset($_POST['radio1'])` etc. – MrTaikoDrummer May 04 '18 at 15:00
What does if(!empty($_POST['submit'])) do? That if it is not empty it's going to start the function? – May 05 '18 at 18:07
Indeed, `empty()` function checks if a variable is empty, it returns TRUE if that's the case. However you have an exclamation mark before the function, which means you are checking if it's NOT empty. – MrTaikoDrummer May 06 '18 at 19:21

Hampus Brynolf · Accepted Answer · 2018-05-03T21:04:37.693

A better approach, as I guess you really are looking for a combination of radio- and checkboxes and that you want to output the checked options:

<h1> Hotel kamer reservering </h1>
<br><br>

<form method="POST">
<input name="roomtype" type="radio" checked="checked" value="éénpersoonskamer">éénpersoonskamer <br><br>
<input name="roomtype" type="radio" value="tweepersoonskamer">tweepersoonskamer <br><br>
<input name="food[]" type="checkbox" value="ontbijt">ontbijt <br><br><br>
<input name="food[]" type="checkbox" value="lunch">lunch <br><br><br>
<input name="food[]" type="checkbox" value="diner">diner <br><br><br>
<input name="submit" type="submit"> 
</form>

<?php 

if(!empty($_POST['submit'])) {
    echo "roomtype: " . $_POST['roomtype'] . "<br>";
    $food = $_POST['food'];
    foreach ($food AS $k => $v) {
        echo "Food $k = $v<br>";
    }
}
?>

You seem have to have the best answer, i will check it later and let you know — , May 04 '18 at 07:09
Your answer worked and was good explained for a beginner like me. Thank you for your time. The radio buttons with the checkbox is a perfect solution. You thought about it and it works good. Thanks — , May 05 '18 at 17:52

Undefined index PHP with echo radio buttons value

3 Answers3