In disarray sorting $array

[furlanut]

I have added 3 radio buttons to a form (no errors prior to this) for option to sort fetch_array result by field. I assume this is best done from the array but am making no progress - the results of $name,print_r($array) and tables are correct but no sorting.
This Notice appears: **Uninitialized string offset: **0 in C:........on line 78
from this extract

<form method="post" name="search" action="workingjoinIDtest.php"/>
        <font family = "arial,verdana,sans-serif" color="#3F7cef"size="4"/>Enter Ship Name or IMO</font>
        <input type="text"  name="name" size="25" maxlength ="35"/>
        <input type="image" name="submit" src="texts/cooltext591383228.png" onmouseover="this.src='texts/cooltext591383228MouseOver.png';" onmouseout="this.src='texts/cooltext591383228.png';" alt="search"><br/> 
        <font family = "arial,verdana,sans-serif" color="#3F7cef"size="4">
        <p><label><input type="radio" name="sequence" value="alpha" checked="yes">Sort A-Z</p>
        <p><label><input type="radio" name="sequence" value="tons">Sort by GRT</p>
        <p><label><input type="radio" name="sequence" value="built">Sort by Year Built</p></font>        
</form>
<div class="printarea"/>         <!--line 43 -->              
<?php                                    //4 MySQL queries-allnames,launch,fate,imocode
if (isset($_POST['name'])) $name = ($_POST ['name']);
else $name = "no name entered";                     //display "no name entered"
if($name =="")                              //if submit pressed with no name entered
{
echo "<p><font color='red' size='6px'>You have not entered a name</font></p>";
exit;
echo"<br />";
}
require_once 'dbconnect.php';
  $name = strtoupper($name);
  $name = strip_tags($name);
  $name = trim ($name); 
  $name = mysql_real_escape_string($name);        // line 57                
$query = "(SELECT * FROM launch JOIN allnames ON launch.id=allnames.id JOIN fate ON fate.id=allnames.id JOIN imocode ON imocode.id=fate.id WHERE name1 LIKE '$name%' OR name2 LIKE '$name%' OR name3 LIKE '$name%' OR name4 LIKE '$name%' OR name5 LIKE '$name%' OR name6 LIKE '$name%' OR name7 LIKE '$name%' OR name8 LIKE '$name%' OR name9 LIKE '$name%' OR name10 LIKE '$name%' OR name11 LIKE '$name%' OR name12 LIKE '$name%'OR name13 LIKE '$name%' OR name14 LIKE '$name%' OR name15 LIKE '$name%'OR name16 LIKE '$name%' OR name17 LIKE '$name%')UNION(SELECT * FROM launch JOIN allnames ON launch.id=allnames.id JOIN fate ON fate.id=allnames.id JOIN imocode ON imocode.id=fate.id WHERE code LIKE '%$name%')";
$result = mysql_query($query);
if (!$result) die ("Database access failed: " . mysql_error());
$rows=mysql_num_rows($result);
echo "<font color='#3F7cef'size='4'/>You searched for:</font>";
echo "<p>";                              //<br /> justifies left and leaves no spaces
echo "<font color='#3F7cef'size='6'>";
require_once "fix_it.php";                      // works equally with name and code input
echo fix_it($name); 
echo "</font>";
if (mysql_num_rows($result)== 0)                    //line 68
echo "<p><font color='red'size='6px'>No data found for your request. Try a different query</font>";
while($row = mysql_fetch_array($result)){
$array = $row;                          
echo "<br />";
echo "<p><font color='#3F7cef'size='5'>$row[32]</font>";       // sets imocode field
if (!function_exists('compare_tons')){
if($sequence='tons') {
function compare_tons($a,$b)
{
return strnatcmp($a['tons'],$a['tons']);
}
uasort($array,"compare_tons");
}
}                                               
print_r($array);                           // enable this line to show all fields in array
    require_once "launch_tableID.php";                 //prints launch table with ID number
    echo launch_tableID();
    echo "<tr><td>$row[0]</td><td>$row[1]</td><td>$row[2]</td><td>$row[3]</td><td>$row[4]</td><td>$row[5]</td><td>"; 
if($row[6] > 0000-00-00)

...continues to end ?>

I must be completely wrong, can someone point me in right direction, please ?

return strnatcmp($a['tons'],$a['tons']);

Is that the line?

[gon1387]

As diafol pointed, you're comparing the argument $a on its self and not on $b:

function compare_tons($a,$b)
{
// compares string $a['tons'] from $a['tons']
// OR SHOULD THIS BE $a['tons'] from $b['tons']
return strnatcmp($a['tons'],$a['tons']);
}

[furlanut]

Thank you for pointing out the elementary error.
Line 78 now shows: $a['tons'],$b['tons']
After input of $name and radio value='tons'
The display is 190 of this:

( ! ) Notice: Uninitialized string offset: 0 in C:\......php on line 78
Call Stack
#   Time    Memory  Function    Location
1   0.0009  406272  {main}( )   ..\workingjoinIDtest.php:0
2   0.1093  431232  uasort ( )  ..\workingjoinIDtest.php:80
3   0.1093  431488  compare_tons( ) ..\workingjoinIDtest.php:0

followed by the result in proper format but not sorted by field 'tons'

[furlanut]

I have amended the code and no warnings/errors now show. But the sorting of the arrays according to the selected radio button using function compare_tons is not working.
Am I taking the wrong approach or misunderstanding the process of sorting ?

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
 "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en">
<body>
<form method="post" name="search" action="radiotest2.php"/>
        <font family = "arial,verdana,sans-serif" color="#3F7cef"size="4"/>Enter Ship Name or IMO</font>
        <input type="text"  name="name" size="25" maxlength ="35"/>
        <font family = "arial,verdana,sans-serif" color="#3F7cef"size="4">
        <input type="image" name="submit" src="texts/cooltext591383228.png" onmouseover="this.src='texts/cooltext591383228MouseOver.png';" onmouseout="this.src='texts/cooltext591383228.png';" alt="search"><br/> 
        <p><label><input type="radio" name="sequence" value="alpha" checked="yes">Sort A-Z</label>
        <label><input type="radio" name="sequence" value="tons">Sort by GRT</label>
        <label><input type="radio" name="sequence" value="built">Sort by Year Built</label></p></font>               
</form>
<div class="printarea"/>         <!--line 14 -->              
<?php 
error_reporting (E_ALL ^ E_NOTICE);                                 
if (isset($_POST['name'])) $name = ($_POST ['name']);
else $name = "no name entered";
if (isset($_POST['sequence'])) $sequence=($_POST['sequence']);
$selected_radio = $_POST['sequence'];
//print $selected_radio;
if ($selected_radio == 'alpha'){
$alpha_status= 'checked';
}
if ($selected_radio == 'tons'){
$tons_status= 'checked';
}
if ($selected_radio == 'built'){
$built_status= 'checked';
}                                               
require_once 'dbconnect.php';
  $name = strtoupper($name);
  $name = strip_tags($name);
  $name = trim ($name); 
  $name = mysql_real_escape_string($name);                  
$query = "(SELECT * FROM launch JOIN allnames ON launch.id=allnames.id JOIN fate ON fate.id=allnames.id JOIN imocode ON imocode.id=fate.id WHERE name1 LIKE '$name%' OR name2 LIKE '$name%' OR name3 LIKE '$name%' OR name4 LIKE '$name%' OR name5 LIKE '$name%' OR name6 LIKE '$name%' OR name7 LIKE '$name%' OR name8 LIKE '$name%' OR name9 LIKE '$name%' OR name10 LIKE '$name%' OR name11 LIKE '$name%' OR name12 LIKE '$name%'OR name13 LIKE '$name%' OR name14 LIKE '$name%' OR name15 LIKE '$name%'OR name16 LIKE '$name%' OR name17 LIKE '$name%')UNION(SELECT * FROM launch JOIN allnames ON launch.id=allnames.id JOIN fate ON fate.id=allnames.id JOIN imocode ON imocode.id=fate.id WHERE code LIKE '%$name%')";
$result = mysql_query($query);
if (!$result) die ("Database access failed: " . mysql_error());
$rows=mysql_num_rows($result);
echo "<font color='#3F7cef'size='4'/>You searched for:</font>";
echo "<p>";                              //<br /> justifies left and leaves no spaces  line 41
echo "<font color='#3F7cef'size='6'>";
require_once "fix_it.php";                      // works equally with name and code input
echo fix_it($name); 
echo "</font>";
if (mysql_num_rows($result)== 0){                   //line 
echo "<p><font color='red'size='6px'>No data found for your request. Try a different query</font>";
}
$array=array();                             //absence of this line gives warning:uasort() expects parameter 1
while($row = mysql_fetch_array($result)){               //assoc only displays [keys]
$array = $row;                              //$array[] increments array to each ID
echo "<p><font color='#3F7cef'size='5'>$row[32]</font>";                // sets imocode field;                                                     
print_r($array);                                // or echo
}                                                       
if(!function_exists(compare_tons)){
if ($tons_status='checked'){
function compare_tons($a,$b)
{
return strnatcmp($a['tons'],$b['tons']);
}
uasort($array,'compare_tons');                                     // line 61
}
}

?>
    </body>
    </html>

Hoping somebody can explain sorting of arrays by field or direct me towards a new approach.

Why don't you just sort in the sql query with an ORDER BY clause? Make the clause dynamic with a php variable, e.g.

switch($_POST['sequence']){
    case 'az': 
        $sort = 'field1, field2, field3';
        break;
    case 'date': 
        $sort = 'field4 DESC';
        break;
    case 'quantity':
        $sort = 'field17';
        break;
    default:
        $sort = 'field1';
}

$sql = "SELECT field1, field2, field3, field4, field17 FROM table1 ORDER BY $sort";

Another idea struck me. You've got helluva query there. I'm no expert, but you may find creating indexes on search fields and then doing fulltext matches in boolean mode useful:

$sql = "SELECT field1, field2, field3, field4 FROM table1 WHERE MATCH (`field2`, `field3`) AGAINST ('{$name}*' IN BOOLEAN MODE)";

Type of thing - gets rid of all the 'OR's
Creating fulltext indexes can be a bit of a chore though.