Why does this script not form a filled table?

astoller

<body>
<?php
$link = mysql_connect('localhost', 'phoenixm', 'adrian') or die('Could not connect');
mysql_select_db('phoenixm_phoenixm') or die('Could not select database');
$result = mysql_query('SELECT TRIM(url) AS url, TRIM(email) AS email, TRIM(company) AS company, catname, catno FROM newtable2') or die('Query failed');
// put in start of the function display-contact" here from p 177 in book
//show contacts in a html table
function displaycontacts($result)
{
echo "<h1>phoenix contact list</h1>\n";
//start with headers
echo "\n<table>\n<tr>\n" .
"\n\t<th>url</th>" .
"\n\t<th>email</th>" .
"\n\t<th>Company</th>" .
"\n\t<th>Category name</th>" .
"\n</tr>";

// keep doing this until there are no rows left
while ($row=@mysql_fetch_row($result))
{
//start a table row
echo "\n<tr>";
//and print out each elements as a separate td
foreach($row as $data)
echo "\n\t<td>$data </td>";
// finish row
echo "\n</tr>";
// finish table
echo "\n</table>\n";
}

$query="select * from newtable2";
//Display the results
displaycontacts($result);

?>
</body>
</html>

paulnaj

Hi astoller,

Have you done any debugging :queasy:

There are a list of basic errors in that code. If you need any help learning how to debug, then come back.

Here's a couple of tips ...

1) Always use {} to contain 'loop' code.
2) Indent your code.
3) Forget using all those \n 's to pretty up your source code
4) In the browser, view the html source.
5) Turn on full error reporting.

Paul.

astoller

Thanks for the reply.
For my better understanding:

I thought the only loops were at
while ($row......line.
where I've got {}
Indent my code.
I'll use [ ] in future postings to indent my questions
(If that's what you meant)
Are the \n occurences causing the prog to fail?
Where do I turn on full error reporting?

paulnaj

OK,

1) foreach($row as $data) has no {}

2 & 3) Fair enough about using the [ PHP ] tags ... but I think that having all the \ n 's just clutter up the code and make it harder to debug. There are much better ways to keep the HTML source tidy in the browser.

4) Viewing the HTML source in the browser is usually my first port of call when things go wrong.

5) If you are able to change the php ini file, then look for the error reporting section and folow the instructions for turning on 'ALL'.

Otherwise, you can simply put the following line ...

error_reporting(E_ALL);

... at the very top of your script.

Anyway, in order to try and find out where you're problems lay, I pushed the code around a bit ...

<html>
<head>
	<title>Test</title>
</head>
<body> 
<?php 
error_reporting(E_ALL);

/////////////////////////////////////////////////////////
function displaycontacts($result){ 
?>
<h1>phoenix contact list</h1>
<table>
	<tr>
		<th>url</th>	
		<th>email</th>
		<th>Company</th>
		<th>Category name</th>
	</tr>
<?php while($row = mysql_fetch_row($result)){ ?>
	<tr>
		<td><?php echo join('</td>
		<td>', $row); ?></td>
	</tr>
<?php } ?>
</table>
<?php
}
/////////////////////////////////////////////////////////

// Go back and edit your connection details out
$link = mysql_connect('localhost', 'XXX', 'XXX') or die('Could not connect'); 

mysql_select_db('phoenixm_phoenixm') or die('Could not select database'); 
$result = mysql_query('SELECT TRIM(url) AS url, TRIM(email) AS email, TRIM(company) AS company, catname, catno FROM newtable2') or die('Query failed'); 

//Display the results 
displaycontacts($result); 
?> 
</body> 
</html>

Hope that helps you along, come back if you don't understand anything or I've typo'd 😉

Paul.

astoller

Thank you very much for all your help

Arthur

astoller

 
while($row = mysql_fetch_row($result)){ ?> 
    <tr> 
        <td><?php echo join('</td> 
        <td>', $row); ?></td> 
    </tr> 
[/php ] 

Trying to understand the join statement.
Join joins all the elements following it?
So in line 3 we'd get
<td> followed by </td><td> and the row elelemnts
Why open then close a <td> with nothing in between ?

paulnaj

OK, suppose we want to create the following table ...

<table border="0" cellpadding="0" cellspacing="0">
	<tr>
		<td>0</td>
		<td>1</td>
		<td>2</td>
	</tr>
</table>

... and keep the HTML looking tidy.

The tds could be first looked at as ...

... where ...

<td> : Comes before the array
0</td><td>1</td><td>2 : Array items separated by '</td><td>'
</td> : Comes after

So we'd use join() like ...

<table border="0" cellpadding="0" cellspacing="0">
	<tr>
<?php 
echo '<td>'.join('</td><td>', $array).'</td>';
?>	
	</tr>
</table>

You can build-in the 'correct' indentation as necessary ...

<table border="0" cellpadding="0" cellspacing="0">
	<tr>
<?php echo '
	<td>'.join('</td>
	<td>', $array).'</td>
';
?>	
	</tr>
</table>

Paul 🙂

astoller

Thanks for clarifying it for me.

If I wanted to print each row on a diffrent
background colour of alterantely :

white
grey
white
grey etc.

can you tell me how to do this with your
exisitng code?

I have various ideas but dont kow the best way to work them into the code.

paulnaj

Hi again astoller,

It's not hard ... just get it clear in your mind what actually has to happen.

What were your ideas?

Paul.

astoller

Well

In the line that starts

<?php while

I need to put in something that
sets the line at colour1
Then we print the line with the echo statement.
Then we need to change this colour to colour2
Then we loop again for the next
row of data from the fetch mysql_fetch statemnt

This time when we print the line bgcolor must
be color2
So I suppose we set up 2 variables:

$color which we put into a html tag
as <bgcolor=$color>
$color can have only 2 values i.e. #eee and #fff
and we put this in

Also
$condition which must change every time
we come to the <?php while statement.

Not sure how to make it truse/false/true
i.e. to alternate on every pass of the loop.

Arthur

thorpe

if ($color == "eee") {
  $color = "fff";
} else {
  $color = "eee";
}

paulnaj

Hi Arthur and Thorpe,

There's a host of ways of doing this (see here for a few alternatives to Thorpe's suggestion).

Probably installer's use of CSS classes is the 'best practice' solution, but whatever get's the job done, eh!

Paul.

astoller

Ok, I tried to work in the code for alterante row colours
but think I made a mistake somewhere.
I struggle with the constant opening and closing
of php code versus html code:

 
error_reporting(E_ALL); 

///////////////////////////////////////////////////////// 
function displaycontacts($result){  

?> 
<h1>phoenix contact list</h1> 
<table> 
    <tr> 
        <th>url</th>     

        <th>email</th> 
        <th>Company</th> 
        <th>Category name</th> 
    </tr> 
<?php 
$bgcolors = array('white', 'yellow', '#C0C0FF'); 
$num_bgcolors = count($bgcolor); 
$counter = 0; 
while($row = mysql_fetch_row($result))
	$bgcolor = $bgcolor[($counter++) % $num_bgcolors]; 
{ ?> 
    <tr> 
        <td bgcolor="'.$bgcolor.'"><?php echo join('</td> 
        <td bgcolor="'.$bgcolor.'">', $row); ?></td> 
    </tr> 
<?php } ?> 
</table> 
<?php 
} 
///////////////////////////////////////////////////////// 

// Go back and edit your connection details out 
$link =  mysql_connect('localhost', 'phoenixm', 'adrian') or die('Could not connect');  

mysql_select_db('phoenixm_phoenixm') or die('Could not select database');  

$result = mysql_query('SELECT TRIM(url) AS url, TRIM(email) AS email, TRIM(company) AS company, catname, catno FROM newtable2') or die('Query failed');  

//Display the results 
displaycontacts($result);

</body>
</html>

paulnaj

It's a typo (mine) :queasy:

Change the line ...

$num_bgcolors = count($bgcolor);

... to ...

$num_bgcolors = count($bgcolors);

Paul.

EDIT: Just noticed something else ... have to answer it later.

paulnaj

OK Arthur, back again ...

The first thing was my typo in the other thread ... just shows how easy it is to make errors like this.

Just add an 's' to $bgcolor in the call to function count() ... that 'counts' the number of elements in the array $bgcolors ... in this case $num_bgcolors = 3.

The second thing was just where you placed the line ...

$bgcolor = $bgcolor[($counter++) % $num_bgcolors];

It's supposed to occur on each 'iteration' of the loop ... so it must be placed within the 'while block' which has the form ...

while(some condition is true){
// execute this code
}

... and that means it comes after the '{', not before like you had it.

It should be ...

while($row = mysql_fetch_row($result)) {
    $bgcolor = $bgcolor[($counter++) % $num_bgcolors];  

 ?>

Paul.

astoller

It doesnt like the line that goes
$bgcolors=$bgcolors with the message
string offset.

(What does the % num thing do?)

error_reporting(E_ALL); 

///////////////////////////////////////////////////////// 
function displaycontacts($result){

<h1>phoenix contact list</h1>
<table>
<tr>
<th>url</th>

<th>email</th>
<th>Company</th>
<th>Category name</th>
</tr>

$bgcolors = array('white', 'yellow', '#C0C0FF'); 
$num_bgcolors = count($bgcolors);              //counts the number of elelents in array $bgcolors
$counter = 0; 
while($row = mysql_fetch_row($result))  //while this condit is true do the following
    {
	$bgcolors = $bgcolors[($counter++) % $num_bgcolors];

 echo join('</td> 
        <td bgcolor="'.$bgcolors.'">', $row);

</td>
</tr>

</table>

} 
///////////////////////////////////////////////////////// 

// Go back and edit your connection details out 
$link =  mysql_connect('localhost', 'phoenixm', 'adrian') or die('Could not connect');  

mysql_select_db('phoenixm_phoenixm') or die('Could not select database');  

$result = mysql_query('SELECT TRIM(url) AS url, TRIM(email) AS email, TRIM(company) AS company, catname, catno FROM newtable2') or die('Query failed');  

//Display the results 
displaycontacts($result);

</body>
</html>

paulnaj

You've added an 's' to more places than I said ... should have been exactly one.

Here's the whole function again ...

///////////////////////////////////////////////////////// 
function displaycontacts($result){   

?> 
<h1>phoenix contact list</h1> 
<table> 
    <tr> 
        <th>url</th>      

        <th>email</th> 
        <th>Company</th> 
        <th>Category name</th> 
    </tr> 
<?php  

$bgcolors = array('white', 'yellow', '#C0C0FF');  

$num_bgcolors = count($bgcolors);  // ADDED 's' HERE
$counter = 0;  

while($row = mysql_fetch_row($result)) { // FIXED brace '{' issue
    $bgcolor = $bgcolor[($counter++) % $num_bgcolors];  

 ?>  

    <tr> 
        <td bgcolor="'.$bgcolor.'"><?php echo join('</td> 
        <td bgcolor="'.$bgcolor.'">', $row); ?></td> 
    </tr> 
<?php } ?>  

</table> 
<?php  

} 
/////////////////////////////////////////////////////////

% is called the modulus operator. It returns the remainder on integer division.

Take any two integers, m and n, say. (E.g. m=13 and n=3)
You can always find another two integers, called q (quotient) and r (remainder) so that ...

m = q*n + r ... where 0 <= r < n

E.g. We want 13 = q*3 + r ( where 0 <= r < 3)
Here, q = 4 and r = 1

Finally, m % n = r ... the remainder

The crucial thing is that ...

0 <= m % n < n

... so you've converted m into a number greater than zero but less than n.

In your case, suppose we put in an extra steps for clarity ...
$n = $num_bgcolors;
$m = ($counter++);
$r = $m % $n;

... and follow the variables in a table to see what's going on ...

+--+--+---------+-------------+
|$m|$n|$m%n = $r|$bgcolors[$r]|
+--+--+---------+-------------+
| 0| 3| 0%3 = 0 |        white|
| 1| 3| 1%3 = 1 |       yellow|
| 2| 3| 2%3 = 2 |      #C0C0FF|
| 3| 3| 3%3 = 0 |        white|
| 4| 3| 4%3 = 1 |       yellow|
| 5| 3| 5%3 = 2 |      #C0C0FF|
| 6| 3| 6%3 = 0 |        white|
| 7| 3| 7%3 = 1 |       yellow|
| 8| 3| 8%3 = 2 |      #C0C0FF|
| 9| 3| 9%3 = 0 |        white|
+--+--+---------+-------------+

... you can see that although $m (which is equal to ($counter++) remember) is getting bigger and bigger, we've still been able to use the % operator on it ($r = $m % $n) to cycle through the correct indices of the $bgcolors array (0, 1, 2, 0, 1, 2, ... etc)

Paul.

astoller

When I run the code I get :

http://www.phoenixmobility.co.uk/arth7.php

It doesn' t sem to like line 26 :

Undefined variable: bgcolor in /home/phoenixm/public_html/arth7.php on line 26

Should we declare $bgcolor before line 26?
this is line 26 :

$bgcolor = $bgcolor[($counter++) % $num_bgcolors];

Sorry to drive you crazy, but I'm learning all the time.
( That % thing is really amazing! )

Arthur

paulnaj

Hi Arthur,

It's just a typo on that line ... go on ... see if you can work out where to put the 's'. 😉

Paul.

astoller

I get it. bgcolor is a differnt thing from bgcolors and takes
a particular element from array bgcolrs for the html statment.

Its now working great, bit I've got a green as a bgcolor for the first which I cant figure where it came from .