Php empty array checking - php

Question

I've a following html table which name contain array. How can i check this array if it's value is empty ?
echo "<input type='radio' name='ch[$roll][$sname][$class]' value='1' /> ";
echo "<input type='radio' name='ch[$id][$sname][$class]' value='0' />";
Currently i'm checking it with following code, it's not working but i know the name is array and it's must be compare with any array function. Can you guys give me a idea ?
if(isset($_POST['ch']))
{
$ch = $_POST['ch'];
if(empty($ch))
echo "<div class='error>Select attendence field. </div>";
}
Regards.
Update: (Full Code)
$action = htmlspecialchars($_SERVER['PHP_SELF'])."?class=$class_from";
echo "<form method='post' action='$action' name='attendence'/>";
echo "<table width='100%' cellpadding='0' cellspacing='0' border='0'>";
echo "<tr>";
echo "<td class='tdhead' valign='top' width='200'><b>Student Name</b></td>";
echo "<td class='tdhead' valign='top' width='250'><b>Roll No</b>
</td>";
echo "<td class='tdhead' valign='top' width='250'><b>Class Name</b>
</td>";
echo "<td class='tdhead' valign='top' width='200'><b>Present / Not present</b>
</td>";
echo "<td class='tdhead' valign='top' width='200'>
Present All <input type= 'checkbox'
onclick='checkAll(this)'</td>";
echo "</tr>";
//start the counter variable
$counter = 1;
while($res2 = mysql_fetch_array($sql2))
{
$id = (int) $res2['id'];
$sname = inputvalid($res2['sname']);
$roll = inputvalid($res2['roll']);
$class = inputvalid($res2['class']);
echo "<tr>";
echo "<td class='tdhead2' valign='top'>$sname</td>";
echo "<td class='tdhead2' valign='top'>$roll</td>";
echo "<td class='tdhead2' valign='top'>$class</td>";
echo "<td class='tdhead2' valign='top'>";
//echo each radio with the counter for this row
echo "<input type='radio' name='ch[$roll][$sname][$class]' value='1' /> ";
echo "<input type='radio' name='ch[$id][$sname][$class]' value='0' />";
echo "</td>";
echo "<td class='tdhead2' valign='top'> </td>";
echo "</tr>";
//add one to the counter
$counter++;
}
echo "<tr>";
echo "<td class='tdhead2'> </td>";
echo "<td class='tdhead2'> </td>";
echo "<td class='tdhead2'> </td>";
echo "<td class='tdhead2'> </td>";
echo "<td class='tdhead2'><input type='submit' value='Record' name='Submit'
class='submit' /></td>";
echo "</tr>";
echo "</table>";
echo "</form>";
if(isset($_POST['Submit']) && $_POST['Submit'] == "Record")
{
if(isset($_POST['ch']))
{
$ch = array_filter($_POST['ch']);
if (empty($ch))
{
echo "<div class='error>Select attendence field. </div>";
}
}
if(count($ch) == 0)
{
echo "<div class='error>Select attendence field. </div>";
}
else
{
foreach ($_POST['ch'] as $roll => $arr1)
{
$roll;
foreach ($arr1 as $name => $arr2)
{
$name;
foreach ($arr2 as $class => $value)
{
$class;
$value;
$sql = mysql_query("INSERT INTO e_attendence VALUES('', '$name', '$roll', '$class',
'$value', '$current_date')");
}
}
}
}
if($sql)
echo "<div class='success'>Succesfully recorded.
</div>";
}

Answer 1

empty() method work for finding whether the array is empty or not.
But for Your solution use below:-
if(isset($_POST['ch']) && $_POST['ch']=='1')
{
$ch = $_POST['ch'];
if(empty($ch))
echo "<div class='error>Select attendence field. </div>";
}
if You want to show a error message when no radio is selected then use below code:-
if(!isset($_POST['ch']) && $_POST['ch']=='')
{
echo "You have not selected any radio button";
}

Answer 2

use empty() instead of isset()
check the comparison table available at the below link
http://php.net/manual/en/types.comparisons.php

Answer 3

try this
print_r($_POST['ch']);

Answer 4

Try this
if(isset($_POST['ch'])){
$ch = array_filter($_POST['ch']);
if (empty($ch)) {
echo "<div class='error>Select attendence field. </div>";
}
}