update array value of a specific key - php

Question

I've got an array containing animals. I print out the array using a foreach loop. I would like to update the value of a specific key, without changing any of the other values which have different keys. I have an update input box next to each key for the value to go in it. When I type a value for key 0, for example, all the other key values change too, not just 0
So my output is something like this:
The value of $_SESSION['0'] is 'cat' // i want to change cat to something else
The value of $_SESSION['1'] is 'dog' // dog to something else
The value of $_SESSION['2'] is 'mouse' /mouse to something else
this is my code and it so frustrating becuase I have added $key to each input in the foreach loop...
**code
<?php
// begin the session
session_start();
// create an array
$my_array=array('cat', 'dog', 'mouse', 'bird', 'crocodile', 'wombat', 'koala', 'kangaroo');
// put the array in a session variable
$_SESSION['animals']=$my_array;
// loop through the session array with foreach
foreach($_SESSION['animals'] as $key=>$value)
{
// and print out the values
echo 'The value of $_SESSION['."'".$key."'".'] is '."'".$value."'".' <br />';
// getting the updated value from input box
if (isset($_POST["submit"])) {
$aaa = $_POST['aaa'];
// setting the session spesific session array value different for each key
$_SESSION['animals'][$key] = $aaa;
}
?>
<form method="post" action="testthis.php">
<input type="text" name="aaa" value="<?php echo $value ; ?>" size="2" />
<input type="submit" value="Add to cart" name="submit"/></div>
</form>
<?php
}
echo"<br/>---------------------------------------------------------<br/>";
//echoing out the results again for the updated version
foreach($_SESSION['animals'] as $key=>$value)
{
// and print out the values
echo 'The value of $_SESSION['."'".$key."'".'] is '."'".$value."'".' <br />';
}
?>

Answer 1

Try following code.
Edits:
1) move isset($_POST["submit"]) outside foreach loop so that it will not update all the sessions.
2) take hidden input with the value of key to be updated so that we can concentrate only on one key which is to be updated.
<?php
// begin the session
session_start();
// create an array
$my_array=array('cat', 'dog', 'mouse', 'bird', 'crocodile', 'wombat', 'koala', 'kangaroo');
// put the array in a session variable
if(!isset($_SESSION['animals']))
$_SESSION['animals']=$my_array;
// move submit code outside of foreach loop
if (isset($_POST["submit"]))
{
$aaa = $_POST['aaa'];
$key_var = $_POST['ke'];
// setting the session spesific session array value different for each key
$_SESSION['animals'][$key_var] = $aaa;
}
// loop through the session array with foreach
foreach($_SESSION['animals'] as $key=>$value)
{
// and print out the values
echo 'The value of $_SESSION['."'".$key."'".'] is '."'".$value."'".' <br />';
// getting the updated value from input box
?>
<form method="post" action="">
<input type="text" name="aaa" value="<?php echo $value ; ?>" size="2" />
<!-- take a hidden input with value of key -->
<input type="hidden" name="ke" value="<?php echo $key; ?>">
<input type="submit" value="Add to cart" name="submit"/></div>
</form>
<?php
}
echo"<br/>---------------------------------------------------------<br/>";
//echoing out the results again for the updated version
foreach($_SESSION['animals'] as $key=>$value)
{
// and print out the values
echo 'The value of $_SESSION['."'".$key."'".'] is '."'".$value."'".' <br />';
}
?>