Finding the Position of a Value in an Array

Use array_search( ) . It returns the key of the found value. If the value is not in the array, it returns false:

$position = array_search($value, $array);
if ($position !== false) {
    // the element in position 

//$position has $value as its 

//value in array $array
}

Use in_array( ) to find if an array contains a value; use array_search( ) to discover where that value is located. However, because array_search( ) gracefully handles searches in which the value isn't found, it's better to use array_search( ) instead of in_array( ). The speed difference is minute, and the extra information is potentially useful:

$favorite_foods = array(1 => 'artichokes', 'bread', 'cauliflower', 'deviled eggs');
 $food = 'cauliflower'; $position = array_search($food, $favorite_foods);
 if ($position !== false)
{
echo "My #$position favorite food is $food";
}
 else {
 echo "Blech! I hate $food!";
 }

Use the !== check against false because if your string is found in the array at position 0, the if evaluates to a logical false, which isn't what is meant or wanted.

If a value is in the array multiple times, array_search( ) is only guaranteed to return one of the instances, not the first instance.