Question

I have a postcode array:

$firstPostcode = array(
    'se1',
    'ec2a',
    'se16',
);

I need to validate users first 4 chars of a uk postcode against the above array.

Problem I have is I need to loop through one char at a time. Some input maybe 4 chars or 3 with a space.

I have tried preg match and in array but can’t solve it after hours of googling

Thanks for any advice.

The problem I am having is its matching the whole array not starting 4 chars

Answer 1

You should be able to match with a single regexp:

$firstPostcode = array(
    'se1',
    'ec2a',
    'se16',
);
$rx = '!^\s*('.implode('|', $firstPostcode).')!i';

if (preg_match($rx, $input)){
    # postcode matches!
}

The creates a regexp like this:

!^\s*(se1 |ec2a|se16)!i

This matches one of your prefixes at the start of the string (skipping any spaces first) and is case-insensitive.