Sort a multidimensional array by key

[wchamber22]

Hi freaks,

 

Got a simple one for ya, I THINK?

 

I have a multi-array that resembles this..

$_SESSION["book_array"] = array(0 => array("plantID" => $plantID, "botanicalName" => $botanicalName, "commonName" => $commonName, "use" => $use));

 

I would like to sort it by the botanicalName key of the inner array before I call the forech loop that renders the display so that after it renders the table the items will be seen alphabetically, code below..

<?php 
$bookOutput = "";
//$plant_use_array = '';
if (!isset($_SESSION["book_array"]) || count($_SESSION["book_array"]) < 1) {
    $bookOutput = '<tr><td colspan="4"><h6>Your Book is EMPTY!</h6></td></tr>';
} else {
// Start the For Each loop
$i = 0; 
    foreach ($_SESSION["book_array"] as $each_item) { 
	$plantID = $each_item['plantID'];
	$botanicalName = $each_item['botanicalName'];
	$botanicalName = stripslashes($botanicalName);
	$commonName = $each_item['commonName'];
	$commonName = stripslashes($commonName);
	$use = $each_item['use'];
	//$x = $i + 1; 
	// Dynamic table row assembly
	$bookOutput .= "<tr>";
	$bookOutput .= '<td><a href="plant_details.php?plantID=' . $plantID . '" id="bodyLink">' . $botanicalName . '</a></td>';
	$bookOutput .= '<td>' . $commonName . '</td>';
	$bookOutput .= '<td><strong>' . $use . '</strong></td>';
	$bookOutput .= '<td><form action="book.php" method="post"><input name="removeBtn" type="submit" value="Remove"/><input name="index_to_remove" type="hidden" value="' . $i . '" /></form></td>';
	$bookOutput .= '</tr>';
	$i++; 
    } 
}
?>

 

Any help would be much appreciated!  Thanks in advance.

[kicken]

Create a comparison function and use usort.  The function will take two arguments, which will be elements of the main array.  Access each arguments 'botanicalName' key and compare them and return the result (as either -1, 0, or 1)

 

[wchamber22]

Thanks Kicken,

 

I believe I am on the right track after exploring the usort function.  Below is what I have come up with thus far, but am still not getting the alphabetical ordered results as I wish.

 

$bookArray = $_SESSION["book_array"];
function botanicalCmp ($a, $b) {
    	if ($a['botanicalName'] == $b['botanicalName'])
        	return 0;
    	if ($a['botanicalName'] < $b['botanicalName'])
         	return -1;
    	return 1;
}
usort($bookArray, 'botanicalCmp');

 

Here is my entire output code, with a little more help I know I can get this, thanks in advance.

 

<?php
$bookOutput = "";
//$plant_use_array = '';
if (!isset($_SESSION["book_array"]) || count($_SESSION["book_array"]) < 1) {
    $bookOutput = '<tr><td colspan="4"><h6>Your Book is EMPTY!</h6></td></tr>';
} else {
$bookArray = $_SESSION["book_array"];
function botanicalCmp ($a, $b) {
    	if ($a['botanicalName'] == $b['botanicalName'])
        	return 0;
    	if ($a['botanicalName'] < $b['botanicalName'])
         	return -1;
    	return 1;
}
usort($bookArray, 'botanicalCmp');
// Start the For Each loop
$i = 0; 
    foreach ($_SESSION["book_array"] as $each_item) { 
	$plantID = $each_item['plantID'];
	$botanicalName = $each_item['botanicalName'];
	$botanicalName = stripslashes($botanicalName);
	$commonName = $each_item['commonName'];
	$commonName = stripslashes($commonName);
	$use = $each_item['use'];
	//$x = $i + 1; 
	// Dynamic table row assembly
	$bookOutput .= "<tr>";
	$bookOutput .= '<td><a href="plant_details.php?plantID=' . $plantID . '" id="bodyLink">' . $botanicalName . '</a></td>';
	$bookOutput .= '<td>' . $commonName . '</td>';
	$bookOutput .= '<td><strong>' . $use . '</strong></td>';
	$bookOutput .= '<td><form action="book.php" method="post"><input name="removeBtn" type="submit" value="Remove"/><input name="index_to_remove" type="hidden" value="' . $i . '" /></form></td>';
	$bookOutput .= '</tr>';
	$i++; 
    } 
}
?>

[wchamber22]

Can anyone help me with this, I have been working all day with no success.  I am too new to php grasp this concept, sorry.

 

Thanks in advance!

[kicken]

usort($bookArray, 'botanicalCmp');

 

    foreach ($_SESSION["book_array"] as $each_item) { 

 

You're sorting the variable $bookArray, but your looping over $_SESSION['book_array'].  You need to sort the same variable you loop over.

 

[wchamber22]

Yeah Kicken that was it, now I feel really dumb.  Anyway thanks again.

 

Kicken >= THE MAN!