Question

I am getting information from a database that I have no control over. The value of “state” is a user entered (and properly cleaned) value, but may be the written out state name or the two letter postal abbreviation. I can easily build an associative array of states and abbreviations. But I was wondering if there is a way, PHP, to determine if a value is in the array of states/abbrev as a key OR a value. So, if you enter “CA” it sees it is a valid two letter key and returns it. If it sees “XY” is NOT a valid key then it retuns a default “OTHER” key (ZZ), but if the user entered input is “New York” it will see it is a valid value and return the associated key, “NY”?

Answer 1

$userInput; // Your user's input, processed using regex for capitals, etc to match DB values for the strings of the states.
// Otherwise, do your comparisons in the conditions within the loop to control for mismatching capitals, etc.

$output = false;

foreach ($stateArray as $abbreviation => $full) // Variable $stateArray is your list of Abbreviation => State Name pairs.
{
    if ($userInput == $abbreviation || $userInput == $full) // Use (strtolower($userInput) == strtolower($abbreviation) || strtolower($userInput) == strtolower($full)) to change all the comparison values to lowercase.
    // This is one example of processing the strings in a way to ensure some flexibility in the user input.
    // However, whatever processing you need to do is determined by your needs.
    {
        $output = array($abbreviation => $full); // If you want a key => value pair, use this.
        $output = $abbreviation; // If you only want the key, use this instead.
        break;
    }
}

if ($output === false)
{
    $output = array("ZZ" => "OTHER"); // If you want a key => value pair, use this.
    $output = "ZZ"; // If you only want the key, use this instead.
}

Edit: I’ve changed the loop so that it checks user input against abbreviation and full state name in one condition instead of having them separate.