How to use index of loop in Post method PHP - php

Question

I need your help! I am trying to save a variable in sql table using Php but I have problem. There are two questions in php, the first concern the continent and the second is depended from the continent. I want to use a loop to check which of the continents has been selected in the first question and then save the value of the second question. I hide the option of unchecked continent using some javascript code (I don't have problem).
The HTML code:
<form method="post" action="">
<fieldset><legend>Continents</legend>
<select id="q1" name="q1">
<option value="1">Africa</option>
<option value="2">Asia</option>
<option value="3">Australia</option>
<option value="4">America</option>
<option value="5">Europe</option>
</select>
<select id="q2" name="Africa">
<option value="1">Choice 1</option>
<option value="2">Choice 2</option>
</select>
<select id="q2" name="Asia">
<option value="1">Choice 1</option>
<option value="2">Choice 2</option>
</select>
<select id="q2" name="Australia">
<option value="1">Choice 1</option>
<option value="2">Choice 2</option>
</select>
<select id="q2" name="America">
<option value="1">Choice 1</option>
<option value="2">Choice 2</option>
</select>
<select id="q2" name="Europe">
<option value="1">Choice 1</option>
<option value="2">Choice 2</option>
</select>
</fieldset>
The Php code
$q1 = $_POST['q1'];
$continents = array("Africa","Asia", "Australia","America","Europe");
for ($i = 1; $i <= 5; $i++) {
if($q1 == $i) {
$q2 = $_POST[$continents[$i-1]]
}
}

Answer 1

Your array should be from 1 to 5 instead of 0 to 4 as you have values 1 to 5 in q1.
Alternatively, I suggest that change your HTML structure to get the continent value in a single line without using loop. You need to change the values of continent like,
<select id="q1" name="q1">
<option value="Africa">Africa</option>
<option value="Asia">Asia</option>
<option value="Australia">Australia</option>
<option value="America">America</option>
<option value="Europe">Europe</option>
</select>
And to get the value of selected continent use $_POST[$_POST['q1']]. For egs, $_POST['q1']=Asia, then $_POST['Asia'] will return the Asia's choice,
$q2= $_POST[$_POST['q1']];

Answer 2

change
$continents =
array(1 => "Africa",
2 => "Asia",
3 => "Australia",
4 => "America",
5 => "Europe");
or
if(($q1-1) == $i) {
$q2 = $_POST[$continents[$i]]
}

Answer 3

First, you may change your select continent HTML:
<select id="q1" name="q1">
<option value="Africa">Africa</option>
<option value="Asia">Asia</option>
<option value="Australia">Australia</option>
<option value="America">America</option>
<option value="Europe">Europe</option>
</select>
Then you could loop over your continents and get the answer:
$q1 = $_POST['q1'];
$continents = array("Africa","Asia", "Australia","America","Europe");
foreach($continents as $continent) {
if ($_POST['q1'] == $continent) {
$q2 = $_POST[$continent];
}
}
Now you have your answer to the second question in $q2.

Answer 4

How about this?
// Always try to seperate logic from your view
// Intialize data
$continents = array("Africa", "Asia", "Australia", "America", "Europe");
// Check for $_POST
if(isset($_POST["q1"])) {
foreach($continents as $id => $continent) {
if($_POST["q1"] == $id) {
// Do something special here
}
}
}
// Render HTML
<form method="post" action="">
<fieldset>
<legend>Continents</legend>
<select id="q1" name="q1">
<!-- Notice that I echo only variables not all of the html -->
<?php foreach($continents as $id => $continent) { ?>
<option value="<?php echo $id; ?>"><?php echo $continent; ?></option>
<?php } ?>
</select>
<select id="q2" name="Africa">
<option value="1">Choice 1</option>
<option value="2">Choice 2</option>
</select>
<select id="q2" name="Asia">
<option value="1">Choice 1</option>
<option value="2">Choice 2</option>
</select>
<select id="q2" name="Australia">
<option value="1">Choice 1</option>
<option value="2">Choice 2</option>
</select>
<select id="q2" name="America">
<option value="1">Choice 1</option>
<option value="2">Choice 2</option>
</select>
<select id="q2" name="Europe">
<option value="1">Choice 1</option>
<option value="2">Choice 2</option>
</select>
</fieldset>
Beautiful thing about my solution is that now you can create whatever array you want and your code will always work.
You can for example SELECT data from database and store them in $continents variable.
$query = "SELECT id, name FROM continents";
$result = mysql_query($query);
$continents = array();
while($row = mysql_fetch_assoc($result)) {
$continents[$row["id"]] = $row["name"];
}
Cool right? :)

Answer 5

I found the solution finally!!!
Replace
$q2 = $_POST[$continents[$i-1]]
with
$q2 = $_POST["{$continents[$i-1]}"];
That solution I wanted!!