I want 0 to be a number, not false

[Wickham]

I've got a form where people will be able to enter a vote from 0 to 10 inclusive. So far I've dealt with the empty box (rejected), entries more than 10 (rejected) and entries 1 to 10 (accepted) but 0 gets treated as an empty box because I can see the echo statement it produces. How do I get 0 in the form treated as a true number?

 

Here's a snippet

 

if(empty($_POST['rating']))

{echo "

Rating must be between 0 and 10.

Use your back button to try again.

"; }

elseif($rating > 10)

{echo "

Rating must be less than 10.

Use your back button to try again.

"; }

elseif($rating

{echo "

You rated {$item} as {$rating} out of 10.

Thank You.

Use your back button to vote for another song.

";}

elseif($rating = 0)

{echo "

You rated {$item} as {$rating} 0 out of 10.

Thank You.

Use your back button to vote for another song.

";}

}

else

{ echo "

Please submit form.

";.........................

 

The last one elseif($rating = 0) doesn't work nor does elseif($rating == 0)

 

The form works well except for rejecting 0.

[falkencreative]

You need to change this line:

 

elseif($rating = 0)

 

to

 

elseif($rating == 0)

 

The double equals (==) checks to see if it is equal to a value, while a single equals (=) sets the value. For example, look at the different between:

 

$i = 3;

if ($i == 3)

[Wickham]

OK, It works on its own, I had it in the wrong order before.

 

However, it's now confused with the Empty situation. If I have the 0 statement first:-

$rating = $_POST['rating'];

$item = $_POST['item'];

if($rating == 0)

{echo "

You rated {$item} as 0 out of 10.

Thank You.

Use your back button to vote for another song.

";}

elseif(empty($_POST['rating']))

{echo "

Rating must be between 0 and 10 inclusive.

Use your back button to try again.

"; }

elseif($rating > 10)

{echo "

Rating must be equal to or less than 10.

Use your back button to try again.

"; }

elseif($rating

{echo "

You rated {$item} as {$rating} out of 10.

Thank You.

Use your back button to vote for another song.

";}

}

else ..........

 

Someone entering 0 gets the "0 out of ten" (correct) but someone submitting an empty input box also gets "0 out of 10 Thank You" instead of Try Again.

 

If I put the Empty situation first:-

 

if(empty($_POST['rating']))

{echo "

Rating must be between 0 and 10 inclusive.

Use your back button to try again.

"; }

elseif($rating == 0)

{echo "

You rated {$item} as 0 out of 10.

Thank You.

Use your back button to vote for another song.

";}

 

then someone entering an empty box gets Try Again but someone entering 0 also gets Try Again, so the first conditional statement sets the value for the next or to put it another way, once the 0 is a number the Empty statement also treats an empty box as a number 0.

>




PHP test



This is testing WampServer2.
if(isset($_POST['sendit']))
{
$rating = $_POST['rating'];
$item = $_POST['item'];
if(empty($_POST['rating'])) 
{echo "
Rating must be between 0 and 10 inclusive.
Use your back button to try again."; }
elseif($rating == 0) 
{echo "
You rated {$item} as 0 out of 10.
Thank You.
Use your back button to vote for another song.";}
elseif($rating > 10) 
{echo "
Rating must be equal to or less than 10.
Use your back button to try again."; }
elseif($rating {echo "
You rated {$item} as {$rating} out of 10.
Thank You.
Use your back button to vote for another song.";}
}
else 
{ echo "
Please submit form.";
?>
</pre>
<form action="test-form-conditional-statementa.php" method="post">

Song 1
Song 2

Rating (out of 10 please):  

</form>
<br>}<br>?><br><p>Other page content here.</p>
<br><br><br

Edited January 22, 2009 by Wickham

[falkencreative]

Could you bypass this by only allowing people to vote 1 through 10, and 0 would represent no vote?

[Wickham]

Yes I could, but I'm trying to learn. I realise that 0 is treated as false in Boolean so your code gets one part of the code working to make it true but for some reason the Empty statement and the 0 statement are linked and give the same result so depending on the order, one of them is wrong.

 

Somewhere I need to convert a true to false or vice versa.

[falkencreative]

OK, got it... Instead of checking the value, your first if statement should check the string length:

 

if(strlen($rating) == 0)

[lwsimon]

the == comparison operator does type coersion. When you say "if ( $var == 0 )", you're really saying "If you typecast 0 to the type of $var, are they equivalent?"

 

The === operator, on the other hand, tests both value and type.

 

I'm not sure if I"m being clear - its been a long day at work - so here are some examples

 

$var = 0;

if( $var == 0 ){ ... } //this executes
if( $var == false ){ ... } //this executes

if( $var === 0 ){ ... } //this executes
if( $var === false ){ ... } //this does not execute

 

PHP manual entry for comparison operators:

http://us2.php.net/operators.comparison

[Wickham]

With the code I've got in post 3, with the Empty statement first, using elseif($rating == 0) for the second statement the 0 input is treated like an empty box and echos

Rating must be between 0 and 10 inclusive.

Use your back button to try again.

 

which is the incorrect text for 0 input but it's correct for Empty box input. Edit: my guess is that the 0 statement would treat 0 as a number (not false) but the processor gets to the Empty statement first where it treats 0 as Empty (Empty is true - there is no input) and echos the Empty text "Try Again" and stops and never reaches the 0 statement.

 

It's the same using if(strlen($rating) == 0)

 

If I reverse the order and put the Empty statement second using if($rating == 0) for the 0 statement first I get

You rated Song 1 as 0 out of 10.

Thank You.

Use your back button to vote for another song.

 

for both a 0 input (correct) and an empty box input (wrong - it must now be treating an empty box as Empty - there is an input of 0 which is now a number therefore Empty is false).

 

If i use if(strlen($rating) == 0) for the first 0 statement both empty and 0 inputs wrong, they have echo text swapped.

 

I haven't tried lwsimon's solution yet.

Edited January 23, 2009 by Wickham

[Wickham]

I've found the answer. The problem as I said was that when someone enters 0 it's treated like Empty so all my different attempts made Empty the same text as 0, except one where the Empty and 0 produced different echo text, but swapped. I could have swapped the text but that would have been cheating.

 

It was using elseif(strlen($rating) == 0) but 0 is false so I realised that if I made that elseif(strlen($rating) == 1) it would make it true, even though it's checking whether 0 is in the string. It can also be elseif(strlen($rating) == true).

 

I also decided to change the order so that the more correct options were first and the Empty statement was last if there were no numbers and 0 was not a string 0. I also changed =1 (equal to or over 1) - after numbers over 10 have been rejected.

 

>




PHP test



This is testing WampServer2.
if(isset($_POST['sendit']))
{
$rating = $_POST['rating'];
$item = $_POST['item'];
if($rating > 10) 
{echo "
Rating must be equal to or less than 10.
Use your back button to try again."; }
elseif($rating >= 1) 
{echo "
You rated {$item} as {$rating} out of 10.
Thank You.
Use your back button to vote for another song.";}
elseif(strlen($rating) == true)  //ie true not false 0 or elseif(strlen($rating) == 1)
{echo "
You rated {$item} as 0 out of 10.
Thank You.
Use your back button to vote for another song.";}
elseif(empty($_POST['rating'])) 
{echo "
Nothing entered.
Rating must be between 0 and 10 inclusive.
Use your back button to try again."; }
}
else 
{ echo "
Please submit form.";
?>
</pre>
<form action="test-form-conditional-statementf2.php" method="post">

Song A
Song B

Rating (out of 10 please):  

</form>
<br>}<br>?><br><p>Other page content here.</p>
<br><br><br><br