Userdefined sorting doesnt work

chrisdee

Hello. Here i am again. Im trying to get sorting to work with
the script below. I want it to sort after description in the table,
but it doesnt work as it is. Any solutions/suggestions ?

<b>Food Nutrient Content Table</b></p>

<? 
$d = array( 
'Food', 
'Eatable(%)', 
'Water(g)', 
'Energy(kj)', 
'Protein(g)', 
'Fat(g)', 
'Carbohydrates(g)', 
'Fibre(g)', 
'Sugar(g)', 
'Iron(g)', 
'Vitamine C(mg)' 
); 

echo "<table border=1>"; 
echo "<tr>"; 
foreach ($d as $descript) { 
echo "<td class=o><a class=cd href=$_SERVER[PHP_SELF]?compare=$descript>$descript</a></td>"; 
} 
echo "</tr>"; 

$file = file("food_nutrient_content_table.txt"); 
usort($file, compare); 

foreach ($file as $value) { 
$del=split(";",$value); 
echo "<tr>"; 
  for ($i=0; $i<=10; $i++) { 
   echo "<td class=p>$del[$i]</td>"; 
  } 
echo "</tr>"; 
} 
echo "</table>"; 

function compare($x, $y) { 
if($x[$del[$i]] == $y[$del[$i]]) 
  return 0; 
else if($x[$del[$i]] < $y[$del[$i]]) 
  return -1; 
else 
  return 1; 
} 

?>

mrhappiness

usort($file, 'compare');

and where do you think do those $del values come from (you use them in function compare)

Installer

Since you don't say how "it doesn't work", I'm guessing that you have error reporting/display turned off. Turn them on and tell us what messages you get. And put quotes around "compare": usort($file, 'compare');.

Edit: Like mrhappiness says.

chrisdee

I get no error message. I guess the problem is with the
function somewhere, but I dont know how to do it right.

mrhappiness

Originally posted by mrhappiness
where do you think do those $del values come from (you use them in function compare)

chrisdee

Sorry for asking again, but I still cant get the sorting
to work with my script. Any suggestions ?

leatherback

Let me ask:

Did you look at the comments before:

How doesn't it work
You need to pass $del to the function too, or declare it as being global
is error_reporting switched on

If so, let us know what happened. Otherwise we are searching in the dark.

chrisdee

Thank you for all suggestions, and yes I have read them, but
i did not understand exactly.

Iv updated the script. The problem now is that only the
Food row is sorted. When I click on any of the other rows
nothing happens. Any new suggestions is greatly apreciated ?

Sorry for asking again, but being a programming illiterate,
i need everything in with a spoon🙂

<?

$d = array(
 'Food',
 'Eatable(%)',
 'Water(g)',
 'Energy(kj)',
 'Protein(g)',
 'Fat(g)',
 'Carbohydrates(g)',
 'Fibre(g)',
 'Sugar(g)',
 'Iron(g)',
 'Vitamine C(mg)'
);

echo "<table border=1>";
echo "<tr>";
foreach ($d as $desc) {
 echo "<td class=o><a class=cd href=$_SERVER[PHP_SELF]?sorting=$desc>$desc</a></td>";
}
echo "</tr>";

function sorting($d, $b) {
 if ($d == $b) { return 0; }
 else { return ($d > $b); }
}

$file = file("food_nutrient_content_table.txt");
usort($file, 'sorting');

foreach ($file as $value) {
 $del=split(";",$value);
 echo "<tr>";
  for ($i=0; $i<=10; $i++) {
   echo "<td class=p>$del[$i]</td>";
  }
 echo "</tr>";
}
echo "</table>";

?>

leatherback

I think it is this line:

usort($file, 'sorting');

which, I think, shoulod be:

usort($file, $sorting);

since you want the fsorting field to be variable (?).

If that is the case, $sorting is passed through a link.

You should place this line:

$sorting = $_GET['sorting'];

just after the start of the code (<? ). This will make the passed variable sorting available to the script.

Installer

No, the "usort($file, 'sorting');" line is correct syntactically. The second parameter is the name of the callback function (as a string).

$file should be a two-dimensional array, and you should use "array_multisort()" to sort it, or else rearrange each $file string so that the part you want to sort on is at the front, before calling usort.

leatherback

I do not know these functions well enough, obviously.

If I look at this, I would -in my case- have substracted the colum of values I need to sort by.

Sort them while retaining their original key-values http://nl3.php.net/manual/en/function.asort.php

and then use the key of the sorted sub array to produce the output values.

chrisdee

Thanks for the suggestions. Im afraid im to simple to figure
exacatly how to do this. Any examples is apreciated.

Installer

$file is an array of strings, and is being sorted each time without making any changes to the strings, so of course it's always being sorted by "Food", since that's the first part of the string. One way to solve the problem would be to explode the string in a foreach and re-concatenate it with the desired sorting field in front, calling usort(), then concatenating again to put the fields back in order for displaying.

Or use "array_multisort()".

chrisdee

Ok. How do I do that ?

Installer

Like this:

if (!isset($_GET['sorting'])) {
    $sort_key = 'Food';
} else {
    $sort_key = urldecode($_GET['sorting']);
}
$d = array('Food', 
           'Eatable(%)', 
           'Water(g)', 
           'Energy(kj)', 
           'Protein(g)', 
           'Fat(g)', 
           'Carbohydrates(g)', 
           'Fibre(g)', 
           'Sugar(g)', 
           'Iron(g)', 
           'Vitamine C(mg)'); 

$file = file('food_nutrient_content_table.txt'); 
foreach ($file as $key => $line) {
    $items = explode(';', $line);
    $i = 0;
    foreach ($items as $item) {
        $tmp[$key][$d[$i++]] = trim($item);
    }
}
foreach ($tmp as $key => $line) {
    $tmp2[] = $line[$sort_key];
}
array_multisort($tmp2, SORT_DESC, $tmp);

echo '<table border="1">'; 
echo '<tr>'; 
foreach ($d as $desc) { 
    echo '<td class="o"><a class="cd" href="' . 
         $_SERVER['PHP_SELF'] . '?sorting=' . 
         urlencode($desc) . '">' . $desc . '</a></td>'; 
} 
echo '</tr>'; 
foreach ($tmp as $value) { 
    echo '<tr>'; 
    foreach ($value as $something) { 
        echo '<td class="p">' . $something . '</td>'; 
    } 
    echo '</tr>'; 
}

echo '</table>';

chrisdee

Incredible. Thank you Debugging 101.
It works like a charm.

I wish I had a bit more programming skillz so I could figure
this things out myself. Guess I just have to keep
on practising every day.

Installer

Glad it worked.

BTW, I'm Installer. Debugging 101 is a link in my sig. 🙂

See how "array_multisort()" works? In this case (2D array) just put the elements you want to sort by into a smaller (1D) array, then call the function, passing it the derived array, optional flags, and the whole array.