any three, and only three, in a set of n POST values

[fatkatie]

While I'm playing in PHP, this might be better described as a general algorithm request.  Here's my problem.

 

I have a reentry page that has numerous post values.  In a given set of 7 post values, any 3, and only 3, values must be set.

 

set < 3 || set > 3 == error

 

How would would you code something like that?

 

Do I have to use a loop?

 

Thanks

 

(no - this is not an assignment)

Edited January 11, 2018 by fatkatie

[dodgeitorelse3]

echo "<form name='posttest' action='' method='post'><br />

		Post 1: <input type='text' name='a[]' value='' /><br />

		Post 2: <input type='text' name='a[]' value='' /><br />

		Post 3: <input type='text' name='a[]' value='' /><br />

		Post 4: <input type='text' name='a[]' value='' /><br />

		Post 5: <input type='text' name='a[]' value='' /><br />

		Post 6: <input type='text' name='a[]' value='' /><br />

		Post 7: <input type='text' name='a[]' value='' /><br />

		<input id='tn' type='submit' value='post'>

		</form>";


	echo "<br /><br />";


	$countit = 0;


		foreach($_POST['a'] as $key => $pa)

		{

			if(isset($pa) AND !empty($pa))

			{

				$countit++;

				echo $pa."<br />";

			}

		}


		if($countit >= 4){

			echo "too many post values ($countit)";

		}

			elseif($countit <= 2){

				echo "too few post values ($countit)";

			}

				else{

					echo "Just right ($countit)";

				}	

[kicken]

If your inputs are an array (as demonstrated above), then all you need to do is check if it exists and it's count is 3.

 

$isValid = isset($_POST['selection']) && count($_POST['selection']) == 3;
if ($isValid){
   echo 'Proper amount selected';
} else {
   echo 'Invalid selection.';
}

[Barand]

That would work if they were checkboxes. For text inputs, use array_filter (to remove blanks) before count().