function to check if user text is valid - php

Question

I am trying to make a function so that if the user clicks the Update button AND the text in the textbox is a valid text(only the text from the array should be valid ie. text1, text2, text3). Then, it echo's the number assosiated to the text in the array so if text1 is entered, it should echo 10. I made a function to do it but it says Invalid argument supplied for foreach() on the foreach loop line.
HTML:
<input type='text' id='usertext' name='usertext' size='15' />
<input type='submit' name='update' id='update' value='Update' />
PHP:
public currenttext = 0;
$config['text'] = array(
10 => 'text1',
25 => 'text2',
50 => 'text3'
);
public function set_text($validtext) {
foreach($this->config['text'] as $key => $value) { // <-- foreach loop
if($key == $validtext){
$this->currenttext = $value;
}
}
}
if ($_POST['update') {
$this->set_text($_POST['usertext'));
}

Answer 1

You may try this:
if ( isset($_POST['update']) ) {
$this->set_text( $_POST['usertext'] );
}
Also flip the array;
$config['text'] = array(
'text1' => 10,
'text2' => 25,
'text3' => 50
);
Finally change the set_text method to something like this:
// $validtext could be text1 or text2 or text3 from user
public function set_text($validtext) {
if(array_key_exists($validtext, $this->config['text'])) {
$this->currenttext = $this->config['text'][$validtext];
}
}
Integrate these in your class properly, it'll work. Also check array_key_exists on PHP manual.

Answer 2

Actually, you dont need a foreach loop, alternatively, you could also use array_search() to get the same goal. Consider this example:
<?php
if(isset($_POST['update'])) {
$usertext = $_POST['usertext'];
$config['text'] = array(10 => 'text1', 25 => 'text2', 50 => 'text3');
$key = array_search($usertext, $config['text']);
if($key !== false) {
echo $key;
} else {
// not found
{
exit;
}
?>
<form method="POST">
<input type='text' id='usertext' name='usertext' size='15' /><br/>
<input type='submit' name='update' id='update' value='Update' />
</form>