PHP partial postcode match

Question

I am trying to create a simple postcode form where a users enters a postcode and if the postcode exists, the user is redirected to a link.

So, I have this html form:

<form method="get" action="index.php">
    <input type="text" class="form-control input-lg" name="postcode" id="postcode" placeholder="Postcode">
    <span class="input-group-btn">
    <input class="btn btn-default btn-lg find" name="did_submit" id="submithome" type="submit" value="Find My Matchmaker" class="searchbutton">
    </span>
</form>

And the PHP script:

<?php
  if(isset($_GET['postcode'])){
      $valid_prefixes = array(
          2 => array('NH', 'AQ'),
          3 => array('NZ2', 'GT5'),
          4 => array('NG89', 'NG76')
      );

  foreach($valid_prefixes as $length => $prefixes) {
      if (in_array(substr($_GET['postcode'], 0, $length), $prefixes)) {
          header("Location: http://www.google.com/");
      } else {
          echo "<script> $('#myModal').modal('show') </script>";
      }
      exit;
  }}
?>

So, if the entered postcode is CV or NG, the script will redirect the user to google and if not, a modal would be launched.

Now the question. Obviously, the users would enter CV12DB (full postcode) and they would get the modal as if the postcode doesn't exist. What I am trying to do with the PHP script is to search what the user has entered and if his postcode contains CV or NG or SH, redirect him to google.

I have tried using "preg_match" or using keys instead of the array, but with no luck.. I can't seem to figure out how to make it work.

UPDATE After replacing the code, for some reason, it only recognizes the two-letter array. For example if NG76PL is entered, it doesn't recognize it so it goes to "else"

Your corrected code (which is actually based on Peter van der Wal's answer, not your original question) has an incorrectly placed `exit;`, meaning it is going to quit PHP after the first loop. — IMSoP, Nov 02 '13 at 21:29

Peter van der Wal · Accepted Answer · 2013-11-02T20:28:44.597

1

Should it start with one of those two-letter combinations? Then use:

if (in_array(substr($_GET['postcode'], 0, 2), $validatepostcode) {
    // redirect
}

If you have multiple length prefixes you can use:

for ($i = $min_prefix_length; $i <= $max_prefix_length; $i++) {
    if (in_array(substr($_GET['postcode'], 0, $i), $validatepostcode) {
        // redirect
    }
}

Or (more efficient):

$valid_prefixes = array(
    2 => array('NH', 'AQ'),
    3 => array('NZ2', 'GT5'),
);
foreach($valid_prefixes as $length => $prefixes) {
    if (in_array(substr($_GET['postcode'], 0, $length), $prefixes) {
        // redirect
    }
}

You can use regular expressions like ^(NH|AQ|NZ2|GT5) but I don't think that would be a good solution if you have a lot of options.

edited Nov 02 '13 at 20:28

answered Nov 02 '13 at 19:59

Peter van der Wal

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Well, this works if I have only two-letter combinations, but I will have 2-letter, 3-letter and 4-letter combinations.(such as NG, NG3, NG90) – Razvan B. Nov 02 '13 at 20:17
@emisfera If you have problems with this particular solution, you should comment on it here, not edit the question to make it look like this was your original code. – IMSoP Nov 02 '13 at 21:27
Sorry, I'm new to this and I didn't knew exactly how things work. – Razvan B. Nov 02 '13 at 21:33
Start with the foreach-line, and try to explain to yourself what each line does, I'm confident you will see it, if not post an reply and I'll point it to you – Peter van der Wal Nov 02 '13 at 21:44

PHP partial postcode match

1 Answers1