Php > Arrays

Beginners Array Functions

Beginners Array Functions

I have in the past searched for an area that shows how to use arrays and shows why they do what they do. But only found full scripts or lengthy articles about them, but did not explain in plain english. 

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Below are 3 items that will be used in the first example. I use this method for Admin User maitenance areas of my sites. 

[#] is the KEY of the array 
"..." is the VALUE of the array 

$access_level[0] = "Public"; 
$access_level[5] = "Clan Member"; 
$access_level[10] = "Administrator"; 

To display these items in a drop menu of a form: 

<?php 
echo "<select name=\"access\" size=\"1\">\n"; 
    foreach ($access_level as $access_key => $access_value) { 
        echo "<option value=\"$access_key\">$access_value</option>\n"; 
    } 
echo "</select>\n"; 
?> 
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When using arrays in a form element such as a checkbox, you simple place a [] after the element name. Inside the [] will be the KEY of the array and you can place any value in the brackets such as ID numbers or leave empty. Not all actions require a KEY by most will need a VALUE. 

name=\"fieldname[]\" 

<?php 
echo "<input type=\"checkbox\" name=\"userID[]\" value=\"".$row["userID"]."\">\n"; 
?> 

To use this feature in a query such as update or delete. 

<?php 
foreach ($userID as $user_value) { 
    $sql = mysql_query("UPDATE tablename SET field1='$field1', field2='$field2' WHERE userID = $user_value") or die (mysql_error()); 
    } 
header("Location: index.php"); 
?>