Checar un elemento con particular Value

<?php

$meals = array('Walnut Bun' => 1,

               'Cashew Nuts and White Mushrooms' => 4.95,

               'Dried Mulberries' => 3.00,

               'Eggplant with Chili Sauce' => 6.50,

               'Shrimp Puffs' => 0);

$books = array("The Eater's Guide to Chinese Characters",

               'How to Cook and Eat in Chinese');



// This is true: key Dried Mulberries has value 3.00

if (in_array(3, $meals)) {

  print 'There is a $3 item.';

}

// This is true

if (in_array('How to Cook and Eat in Chinese', $books)) {

  print "We have How to Cook and Eat in Chinese";

}

// This is false: in_array( ) is case-sensitive

if (in_array("the eater's guide to chinese characters", $books)) {

  print "We have the Eater's Guide to Chinese Characters.";

}

?>