[Resolved] Question on array manipulation

[DenisG]

Hi Folks,

I have an array problem that has me clawing the walls,
so I really hope someone can help.

I use the SQL query below to retrieve records from
a PostgreSQL database which are then written into an array.

print_r shows the array for a typical retrieval
as follows:

Array ( [0] => Array ( [firstname] => Stephen [lastname] => Spainhour )
[1] => Array ( [firstname] => Ellen [lastname] => Siever ) [2] => Array
( [firstname] => Nathan [lastname] => Patwardhan ) )

<?php

$bkid=$HTTP_GET_VARS[bookid];

$authors=$db->get_results(
"select a.firstname, a.lastname from authors a, haswritten h
where a.authorid=h.hw_authorid and h.hw_bookid=$bkid", ARRAY_A);

foreach ($authors as $author)

while(list($key, $value) = each($author))
{
$authorstring= " $value ";
echo $authorstring;
}
?>

<BR><BR>

<? print_r($authors); ?>
<BR>

In my example, the value
for $authorstring inside the while loop would be:

Stephen Spainhour Ellen Siever Nathan Patwardhan

Outside the while loop, the string is truncated to the
last element of the array, i.e.:
Patwardhan

I have two problems that I can't solve.

1. How can I re-format the string from the above
   to:
   Stephen,Spainhour;Ellen,Siever;Nathan,Patwardhan

and

2. How can I keep the re-formatted value outside the while loop so that I can use it later for other purposes, e.g
   to display it in a form field for possible updating?

thanks in advance,

Denis Grannell

[dalecosp]

What about:

<?php 

$bkid=$HTTP_GET_VARS[bookid]; 
$sql="select a.firstname, a.lastname from authors a, haswritten h 
where a.authorid=h.hw_authorid and h.hw_bookid=$bkid";
$result=mysql_query($sql);
$authors=mysql_fetch_array($result);

while ($z<count(authors)) {
   if (($z==0) || (($z!=1) && ($z % 2==0))) {
      $authors[$z]=$authors[$z].",";
   else {
      $authors[$z]=$authors[$z].";";
   }
}
?>

OOh, though, that'd not work because $authors is an associative array, not numerically keyed... hold the phone...

Maybe this?

 <?php  

$bkid=$HTTP_GET_VARS[bookid];  

$sql="select a.firstname, a.lastname from authors a, haswritten h  

where a.authorid=h.hw_authorid and h.hw_bookid=$bkid"; 
$result=mysql_query($sql); 
$authors=mysql_fetch_array($result); 

$count=(count($authors)/2);
while ($z<$count) { 
   if (($z==0) || (($z!=1) && ($z % 2==0))) { 
      $authors[$z][$lastname]=$authors[$z][$lastname].";"; 
   else { 
      $authors[$z][$firstname]=$authors[$z][$firstname].","; 
   } 
} 
?>

Well, I gotta run, but maybe it works? Or, it'll at least give you an idea. I'll check when I get back and see how it went. Or, maybe you'll luck out and somebody SMART will help, 🙂

[DenisG]

No luck I'm afraid. If the value of $authors would be displayed
by echoing it, then it appears to be empty in both code
examples :-(

thanks all the same.

Denis

[dalecosp]

OK, big oops, 'cuz I called mysql functions...and, as usual, a bit of a hurry. Same this time, but why not keep trying?

<?php 

$bkid=$HTTP_GET_VARS[bookid]; 

$authors=$db->get_results( 
"select a.firstname, a.lastname from authors a, haswritten h 
where a.authorid=h.hw_authorid and h.hw_bookid=$bkid", ARRAY_A); 

while ($z<count($authors)) {  

        $authors[$z]['lastname']=$authors[$z]['lastname'].";";  

        $authors[$z]['firstname']=$authors[$z]['firstname'].",";  

}

while ($x<count($authors)) {  

   echo $authors[$x]['firstname']." ".$authors[$x]['lastname']."<br>";

???

[DenisG]

Still no luck I'm afraid. I copied and pasted your code into the
php script but it doesn't apprear to have any effect. The webserver log shows a parse error. I've pasted a complete
script with your syntax at the end of this posting as well as
the excerpt from the logfile. If I put in the closing double bracket
in the second while loop that I think you overlooked, then the script will loop forever because $x always appears to be less than count($authors)
Are you sure there should be square brackets around $z?
E.g. I tried echoing $authors[0]['lastname']; on the following
array which has only one author's name and it doesn't produce any output at all.

Array ( [0] => Array ( [firstname] => John [lastname] => Dough ) )

complete script:

<?php

$bkid=$HTTP_GET_VARS['bookid'];

#

$authors=$db->get_results(
"select a.firstname, a.lastname from authors a, haswritten h
where a.authorid=h.hw_authorid and h.hw_bookid=$bkid",ARRAY_A);

while ($z<count($authors)) {
$authors[$z]['lastname']=$authors[$z]['lastname'].";";
$authors[$z]['firstname']=$authors[$z]['firstname'].",";
}

while ($x<count($authors)) {
echo $authors[$x]['firstname']." ".$authors[$x]['lastname']."<br>";

?>

logfile message:
[Thu Jun 19 13:19:10 2003] [error] PHP Parse error: parse error in /local/htdocs/test-librarycat/update-request.php on line 20

Denis

[DenisG]

I've made some progress with formatting my string. If I use the following syntax I can build up the string of authors formatted the way I need it.
This will produce e.g.:
John,Dough;Jane,Dough;

This makes me ecstatic.

foreach ($authors as $author){
$authstring=$author->lastname.",".$author->firstname.";";
echo $authstring;
}

echo $authstring;

My problem is still that it is only inside the foreach loop!
The second echo shows that $authstring is now truncated to
"Jane,Dough;". What I need now is a way to preserve the concatenated string.

Denis

[HalfaBee]

You need a .=

foreach ($authors as $author){
$authstring .= $author->lastname.",".$author->firstname.";";
echo $authstring;
}

This adds the strings together.

HalfaBee

[DenisG]

HalfaBee. I owe you a serious beer!. If you're ever in Munich let me know and I'll repay my debt.
It is now working fine!!

Many thanks.

Denis